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Start Over Author "Eimer Tuite" Topic biochemistry
19 results on '"Eimer Tuite"'

1. Role of Order in the Mechanism of Charge Transport across Single-Stranded and Double-Stranded DNA Monolayers in Tunnel Junctions

Author

Christian A. Nijhuis, Edward A. Wilkinson, Andrew R. Pike, Ayelet Vilan, Anton Tadich, Lily Bailey, Senthil Kumar Karuppannan, Ziyu Zhang, Eimer Tuite, Dongchen Qi, Nipun Kumar Gupta, James H. R. Tucker, Hybrid Materials for Opto-Electronics, and MESA+ Institute

Subjects
Base pair, UT-Hybrid-D, DNA, Single-Stranded, 02 engineering and technology, Conductivity, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, Article, chemistry.chemical_compound, Molecular wire, Colloid and Surface Chemistry, Monolayer, Electrical conductor, Quantum tunnelling, Electric Conductivity, Temperature, Charge (physics), General Chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, Chemical physics, Nucleic Acid Conformation, 0210 nano-technology, DNA
Abstract

Deoxyribonucleic acid (DNA) has been hypothesized to act as a molecular wire due to the presence of an extended π-stack between base pairs, but the factors that are detrimental in the mechanism of charge transport (CT) across tunnel junctions with DNA are still unclear. Here we systematically investigate CT across dense DNA monolayers in large-area biomolecular tunnel junctions to determine when intrachain or interchain CT dominates and under which conditions the mechanism of CT becomes thermally activated. In our junctions, double-stranded DNA (dsDNA) is 30-fold more conductive than single-stranded DNA (ssDNA). The main reason for this large change in conductivity is that dsDNA forms ordered monolayers where intrachain tunneling dominates, resulting in high CT rates. By varying the temperature T and the length of the DNA fragments in the junctions, which determines the tunneling distance, we reveal a complex interplay between T, the length of DNA, and structural order on the mechanism of charge transport. Both the increase in the tunneling distance and the decrease in structural order result in a change in the mechanism of CT from coherent tunneling to incoherent tunneling (hopping). Our results highlight the importance of the interplay between structural order, tunneling distance, and temperature on the CT mechanism across DNA in molecular junctions.

Published
2021

2. Duplex Healing of Selectively Thiolated Guanosine Mismatches through a Cd2+ Chemical Stimulus

Author

Eimer Tuite, Michael J. Hall, Colette J. Whitfield, Andrew Houlton, Andrew R. Pike, Samantha M. L. Lunn, Agnieszka K. Bronowska, and Samira Hribesh

Subjects
010405 organic chemistry, DNA damage, Organic Chemistry, Stacking, Guanosine, 010402 general chemistry, 01 natural sciences, Biochemistry, Oligomer, 0104 chemical sciences, Nucleobase, chemistry.chemical_compound, chemistry, Duplex (building), Biophysics, Molecular Medicine, Destabilisation, Molecular Biology, DNA
Abstract

The on-column selective conversion of guanosine to thioguanosine (tG) yields modified oligomers that exhibit destabilisation over the fully complementary duplex. Restoration to a stabilised duplex is induced through thio-directed Cd2+ coordination; a route for healing DNA damage. Short oligomers are G-specifically thiolated through a modified on-column protocol without the need for costly thioguanosine phosphoramidites. Addition of Cd2+ ions to a duplex containing a highly disrupted tG central mismatch sequence, 3'-A6 tG4 T6 -5', suggests a (tG)8 Cd2 central coordination regime, resulting in increased base stacking and duplex stability. Equilibrium molecular dynamic calculations support the hypothesis of metal-induced healing of the thiolated duplex. The 2 nm displacement of the central tG mismatched region is dramatically reduced after the addition of a chemical stimuli, Cd2+ ions, returning to a minimized fluctuational state comparable to the unmodified fully complementary oligomer.

Published
2018
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3. Cover Feature: Duplex Healing of Selectively Thiolated Guanosine Mismatches through a Cd2+ Chemical Stimulus (ChemBioChem 11/2018)

Author

Agnieszka K. Bronowska, Andrew R. Pike, Samantha M. L. Lunn, Samira Hribesh, Michael J. Hall, Andrew Houlton, Eimer Tuite, and Colette J. Whitfield

Subjects
chemistry.chemical_compound, chemistry, Duplex (building), Organic Chemistry, Biophysics, Molecular Medicine, Guanosine, Stimulus (physiology), Molecular Biology, Biochemistry, Nucleobase
Published
2018
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4. Contributory presentations/posters

Author

N. Manoj, V. R. Srinivas, A. Surolia, M. Vijayan, K. Suguna, R. Ravishankar, R. Schwarzenbacher, K. Zeth, null Diederichs, G. M. Kostner, A. Gries, P. Laggner, R. Prassl, null Madhusudan, Pearl Akamine, Nguyen-huu Xuong, Susan S. Taylor, M. Bidva Sagar, K. Saikrishnan, S. Roy, K. Purnapatre, P. Handa, U. Varshney, B. K. Biswal, N. Sukumar, J. K. Mohana Rao, A. Johnson, Vasantha Pattabhi, S. Sri Krishna, Mira Sastri, H. S. Savithri, M. R. N. Murthy, Bindu Pillai, null Kannan, M. V. Hosur, Mukesh Kumar, Swati Patwardhan, K. K. Kannan, B. Padmanabhaa, S. Sasaki-Sugio, M. Nukaga, T. Matsuzaki, S. Karthikevan, S. Sharma, A. K. Sharma, M. Paramasivam, P. Kumar, J. A. Khan, S. Yadav, A. Srinivasan, T. P. Singh, S. Gourinath, Neelima Alam, A. Srintvasan, Vikas Chandra, Punit Kaur, Ch. Betzel, S. Ghosh, A. K. Bera, S. Bhattacharya, S. Chakraborty, A. K. Pal, B. P. Mukhopadhyay, I. Dey, U. Haldar, Asok Baneriee, Jozef Sevcik, Adriana Solovicova, K. Sekar, M. Sundaralingam, N. Genov, Dong-cai Liang, Tao Jiang, Ji-ping Zhang, Wen-rui Chang, Wolfgang Jahnke, Marcel Blommers, S. C. Panchal, R. V. Hosur, Bindu Pillay, Puniti Mathur, S. Srivatsun, Ratan Mani Joshi, N. R. Jaganathan, V. S. Chauhan, H. S. Atreya, S. C. Sahu, K. V. R. Chary, Girjesh Govil, Elisabeth Adjadj, Éric Quinjou, Nadia Izadi-Pruneyre, Yves Blouquit, Joël Mispelter, Bernadette Heyd, Guilhem Lerat, Philippe Milnard, Michel Desmadreil, Y. Lin, B. D. Nageswara Rao, Vidva Raghunathan, Mei H. Chau, Prashant Pesais, Sudha Srivastava, Evans Coutinho, Anil Saran, Leizl F. Sapico, Jayson Gesme, Herbert Lijima, Raymond Paxton, Thamarapu Srikrishnan, C. R. Grace, G. Nagenagowda, A. M. Lynn, Sudha M. Cowsik, Sarata C. Sahu, S. Chauhan, A. Bhattacharya, G. Govil, Anil Kumar, Maurizio Pellecchia, Erik R. P. Zuiderweg, Keiichi Kawano, Tomoyasu Aizawa, Naoki Fujitani, Yoichi Hayakawa, Atsushi Ohnishi, Tadayasu Ohkubo, Yasuhiro Kumaki, Kunio Hikichi, Katsutoshi Nitta, V. Rani Parvathy, R. M. Kini, Takumi Koshiba, Yoshihiro Kobashigawa, Min Yao, Makoto Demura, Astushi Nakagawa, Isao Tanaka, Kunihiro Kuwajima, Jens Linge, Seán O. Donoghue, Michael Nilges, G. Chakshusmathi, Girish S. Ratnaparkhi, P. K. Madhu, R. Varadarajan, C. Tetreau, M. Tourbez, D. Lavalette, M. Manno, P. L. San Biagio, V. Martorana, A. Emanuele, S. M. Vaiana, D. Bulone, M. B. Palma-Vittorelli, M. U. Palma, V. D. Trivedi, S. F. Cheng, W. J. Chien, S. H. Yang, S. Francis, D. K. Chang, Renn Batra, Michael A. Geeves, Dietmar J. Manstein, Joanna Trvlska, Pawel Grochowski, Maciej Geller, K. Ginalski, P. Grochowski, B. Lesyng, P. Lavalette, Y. Blouquit, D. Roccatano, A. Amadei, A. Di Nola, H. J. C. Berendsen, Bosco Ho, P. M. G. Curmi, H. Berry, D. Lairez, E. Pauthe, J. Pelta, V. Kothekar, Shakti Sahi, M. Srinivasan, Anil K. Singh, Kartha S. Madhusudnan, Fateh S. Nandel, Harpreet Kaur, Balwinder Singh, D. V. S. Jain, K. Anton Feenstra, Herman J. C. Berendsen, F. Tama, Y. -H. Sanejouand, N. Go, Deepak Sharma, Sunita Sharma, Santosh Pasha, Samir K. Brahmachari, R. Viiavaraghavan, Jyoti Makker, Sharmisllia Dey, S. Kumar, G. S. Lakshmikanth, G. Krishnamoorthy, V. M. Mazhul, E. M. Zaitseva, Borys Kierdaszuk, J. Widengren, B. Terry, Ü. Mets, R. Rigler, R. Swaminathan, S. Thamotharan, N. Yathindra, Y. Shibata, H. Chosrowjan, N. Mataga, I. Morisima, Tania Chakraharty, Ming Xiao, Roger Cooke, Paul Selvin, C. Branca, A. Faraone, S. Magazù, G. Maisano, P. Migliardo, V. Villari, Digambar V. Behere, M. Sharique Zahida Waheed Deva, M. Brunori, F. Cutruzzolà, Q. H. Gibson, C. Savino, C. Travaglini-Allocatelli, B. Vallone, Swati Prasad, Shyamalava Mazumdar, Samaresh Mitra, P. Soto, R. Fayad, I. E. Sukovataya, N. A. Tyulkova, Sh. V. Mamedov, B. Aktas, M. Canturk, B. Aksakal, R. Yilgin, K. I. Bogutska, N. S. Miroshnichenko, S. Chacko, M. DiSanto, J. A. Hypolite, Y-M. Zheng, A. J. Wein, M. Wojciechowski, T. Grycuk, J. Antosiewicz, Marc A. Ceruso, Alfredo Di Nola, Subhasis Bandvopadhvay, Bishnu P. Chatterjee, Devapriva Choudhury, Andrew Thompson, Vivian Stojanoff, Jerome Pinkner, Scott Hultgren, Stefan Khight, Delphine Flatters, Julia Goodfellow, Fumi Takazawatt, Minoru Kanehisa, Masaki Sasai, Hironori Nakamura, Wang Bao Han, Yuan Zheng, Wang Zhi Xin, Pan xin Min, Vlnod Bhakuni, Sangeeta Kulkarni, Atta Ahmad, Koodathingal Prakash, Shashi Prajapati, Alexey Surin, Tomoharu Matsumoto, Li Yang, Yuki Nakagawa, Kazumoto Kimura, Yoshiyuki Amemiya, Gennady V. Semisotnov, Hiroshi Kihara, Saad Tayyab, Salman Muzammil, Yogesh Kumar, Vinod Bhakuni, Monica Sundd, Suman Kundu, M. V. Jagannadham, Medicherla V. Jagannadham, Bina Chandani, Ruby Dhar, Lalankumar Sinha, Deepti Warrier, Sonam Mehrotra, Purnima Khandelwal, Subhendu Seth, Y. U. Sasidhar, C. Ratna Prabha, Arun Gidwani, K. P. Madhusudan, Akira R. Kinjo, Ken Nishikawa, Suvobrata Chakravarty, Raghavan Varadarajan, K. Noyelle, P. Haezebrouck, M. Joniau, H. Van Dael, Sheffali Dash, Indra Brata Jha, Rajiv Bhat, Prasanna Mohanty, A. K. Bandyopadhyay, H. M. Sonawat, Ch. Mohan Rao, Siddhartha Datta, K. Rajaraman, B. Raman, T. Ramakrishna, A. Pande, J. Pande, S. Betts, N. Asherie, O. Ogun, J. King, G. Benedek, I. V. Sokolova, G. S. Kalacheva, Masashi Sonoyama, Yasunori Yokoyama, Kunihiro Taira, Shigeki Mitaku, Chicko Nakazawal, Takanori Sasakil, Yuri Mukai, Naoki Kamo, Seema Dalal, Lynne Regan, Shigeki Mituku, Mihir Roychoudhury, Devesh Kumar, Dénes Lőrinczv, Franciska Könczöl, László Farkas, Joseph Belagyi, Christoph Schick, Christy A. Thomson, Vettai S. Ananthanarayanan, E. G. Alirzayeva, S. N. Baba-Zade, M. Michael Gromiha, M. Oobatake, H. Kono, J. An, H. Uedaira, A. Sarai, Kazufumi Takano, Yuriko Yamagata, Katsuhide Yutani, Gouri S. Jas, Victor Muñoz, James Hofrichter, William A. Eaton, Jonathan Penoyar, Philip T. Lo Verde, J. Kardos, Á. Bódi, I. Venekei, P. Závodszky, L. Gráf, András Szilágyi, Péter Závodszky, R. D. Allan, J. Walshaw, D. N. Woolfson, Jun Funahashi, Savan Gupta, M. Mangoni, P. Roccatano, Gosu Ramachandraiah, Nagasuma R. Chandra, Barbara Ciani, Derek N. Woolfson, Usha B. Nair, Kanwal J. Kaur, Dinakar M. Salunke, Chittoor P. Swaminathan, Avadhesha Surolia, A. Pramanik, P. Jonasson, G. Kratz, O. T. Jansson, P. -Å. Nygren, S. Ståhl, K. Ekberg, B. -L. Johansson, S. Uhlén, M. Uhlén, H. Jörnvall, J. Wahren, Karin Welfle, Rolf Misselwitz, Wolfgang Höhne, Heinz Welfle, L. G. Mitskevich, N. V. Fedurkina, B. I. Kurganov, Gotam K. Jarori, Haripada Maity, J. Guharay, B. Sengupta, P. K. Sengupta, K. Sridevi, S. R. Kasturi, S. P. Gupta, Gunjan Agarwal, Suzanne Kwong, Robin W. Briehl, O. I. Ismailova, N, A. Tyulkova, C. Hariharan, D. Pines, E. Pines, M. Zamai, R. Cohen-Luria, A. Yayon, A. H. Parola, M. J. Padya, G. A. Spooner, D. N. Woolfeon, Panchan Bakshi, D. K. Bharadwaj, U. Sharma, N. Srivastava, R. Barthwal, N. R. Jagannathan, Keiko Matsuda, Takaaki Nishioka, Nobuhiro Go, T. Aita, S. Urata, Y. Husimi, Mainak Majumder, Nicola G. A. Abrescia, Lucy Malinina, Juan A. Subirana, Juan Aymami, Ramón Eritxa, Miquel Coll, B. J. Premraj, R. Thenmalarchelvi, P. Satheesh Kumar, N. Gautham, Lou -Sing Kan, null Ming-Hou, Shwu-Bin Lin, Tapas Sana, Kanal B. Roy, N. Bruant, D. Flatters, R. Lavery, D. Genest, Remo Rons, Heinz Sklenar, Richard Lavery, Sudip Kundu, Dhananjay Bhattacharyya, Debashree Bandyopadhyay, Ashoke Ranjan Thakur, Rabi Majumdar, F. Barceló, J. Portugal, Sunita Ramanathan, B. J. Rao, Mahua Gliosli, N. Vinay Kumar, Umesh Varshney, Shashank S. Pataskar, R. Sarojini, S. Selvasekarapandian, P. Kolandaivel, S. Sukumar, P. Kolmdaivel, Motilal Maiti, Anjana Sen, Suman Das, Elisa Del Terra, Chiara Suraci, Silvia Diviacco, Franco Quadrifoglio, Luigi Xodo, Arghya Ray, G. Karthikeyan, Kandala V. R. Chary, Basuthkar J. Rao, Anwer Mujeeb, Thomas L. James, N. Kasyanenko, E. E. F. Haya, A. Bogdanov, A. Zanina, M. R. Bugs, M. L. Cornélio, M. Ye. Tolstorukov, Nitish K. Sanval, S. N. Tiwari, Nitish K. Sanyal, Mihir Roy Choudhury, P. K. Patel, Neel S. Bhavesh, Anna Gabrielian, Stefan Wennmalm, Lars Edman, Rudolf Rigler, B. Constantinescu, L. Radu, I. Radulcscu, D. Gazdaru, Sebastian Wärmländer, Mikael Leijon, Setsuyuki Aoki, Takao Kondo, Masahiro Ishiura, V. A. Pashinskaya, M. V. Kosevich, V. S. Shelkovsky, Yu. P. Blagoy, Ji-hua Wang, R. Malathi, K. Chandrasekhar, E. R. Kandimalla, S. Agrawal, V. K. Rastogi, M. Alcolea Palafox, Chatar Singh, A. D. Beniaminov, S. A. Bondarenko, E. M. Zdobnov, E. E. Minyat, N. B. Ulyanov, V. I. Ivanov, J. S. Singh, Kailas D. Sonawane, Henri Grosjean, Ravindra Tewari, Uddhavesh B. Sonavane, Annie Morin, Elizabeth A. Doherty, Jennifer A. Doudna, H. Tochio, S. Sato, H. Matsuo, M. Shirakawa, Y. Kyogoku, B. Javaram, Surjit B. Dixit, Piyush Shukla, Parul Kalra, Achintya Das, Kevin McConnell, David L. Beveridge, W. H. Sawyer, R. Y. S. Chan, J. F. Eccelston, Yuling Yan, B. E. Davidson, Eimer Tuite, Bengt Norden, Peter Nielsen, Masayuki Takahashi, Anirban Ghosh, Manju Bansal, Frauke Christ, Hubert Thole, Wolfgang Wende, Alfred Pingoud, Vera Pingoud, Pratibha Mehta Luthra, Ramesh Chandra, Ranjan Sen, Rodney King, Robert Weisberg, Olaf F. A. Larsen, Jos Berends, Hans A. Heus, Cornelis W. Hilbers, Ivo H. M. van Stokkum, Bas Gobets, Rienk van Grondelle, Herbert van Amerongen, HE. Sngrvan, Yu. S. Babayan, N. V. Khudaverdian, M. Gromiha, F. Pichierri, M. Aida, P. Prabakaran, K. Sayano, Saulius Serva, Eglė Merkienė, Giedrius Vilkaitis, Elmar Weinhold, Saulius Klimašauskas, Eleonora Marsich, Antonella Bandiera, Giorgio Manzini, G. Potikyan, V. Arakelyan, Yu. Babayan, Alex Ninaber, Julia M. Goodfellow, Yoichiro Ito, Shigeru Ohta, Yuzuru Husimi, J. Usukura, H. Tagami, H. Aiba, Mougli Suarez, Elia Nunes, Deborah Keszenman, E. Carmen Candreva, Per Thyberg, Zeno Földes-Papp, Amita Joshi, Dinesh Singh, M. R. Rajeswari, null Ira, M. Pregetter, H. Amenitsch, J. Chapman, B. N. Pandev, K. P. Mishra, E. E. Pohl, J. Sun, I. I. Agapov, A. G. Tonevitsky, P. Pohl, S. M. Dennison, G. P. Gorbeako, T. S. Dynbko, N. Pappavee, A. K. Mishra, Prieto Manuel, Almeida Rodrigo, Loura Luis, L. Ya. Gendel, S. Przestalski, J. Kuczera, H. Kleszczyńska, T. Kral, E. A. Chernitsky, O. A. Senkovich, V. V. Rosin, Y. M. Allakhverdieva, G. C. Papageorgiou, R. A. Gasanov, Calin Apetrei, Tudor Savopol, Marius Balea, D. Cucu, D. Mihailescu, K. V. Ramanathan, Goran Bačić, Nicolas Sajot, Norbert Garnier, Serge Crouzy, Monique Genest, Z. S. Várkonyi, O. Zsiros, T. Farkas, Z. Combos, Sophie Cribier, I. F. Fraceto, S. Schreier, A. Spisni, F. de Paula, F. Sevšek, G. Gomišček, V. Arrigler, S. Svetina, B. Žekš, Fumimasa Nomura, Miki Nagata, Kingo Takiguchi, Hirokazu Hotani, Lata Panicker, P. S. Parvathanathan, A. Ishino, A. Saitoh, H. Hotani, K. Takiguchi, S. Afonin, A. Takahashi, Y. Nakato, T. Takizawa, Dipti Marathe, Kent Jørgensen, Satinder S. Rawat, R. Rukmini, Amitabha Chattopadhyay, M. Šentiurc, J. Štrancar, Z. Stolič, K. Filipin, S. Pečar, S. C. Biswas, Satyen Sana, Anunay Samanta, Koji Kinoshita, Masahito Yamazaki, Tetsuhiko Ohba, Tai Kiuchi, null Yoshitoshi, null Kamakura, Akira Goto, Takaaki Kumeta, Kazuo Ohki, I. P. Sugar, T. E. Thompson, K. K. Thompson, R. L. Biltonen, Y. Suezaki, H. Ichinose, M. Akivama, S. Matuoka, K. Tsuchihashi, S. Gasa, P. Mattjus, J. G. Molotkovsky, H. M. Pike, R. E. Brown, Ashish Arora, Jörg H. Kleinschmidt, Lukas K. Tamm, O. G. Luneva, K. E. Kruglyakova, V. A. Fedin, O. S. Kuptsoya, J. W. Borst, N. V. Visser, A. J. W. G. Visser, T. S. Dyubko, Toshihiko Ogihara, Kiyoshi Mishima, A. L. Shvaleva, N. Č. Radenović, P. M. Minić, M. G. Jeremić, Č. N. Radenović, T. F. Aripov, E. T. Tadjibaeva, O. N. Vagina, M. V. Zamaraeva, B. A. Salakhutdinov, A. Cole, M. Poppofl, C. Naylor, R. Titball, A. K. Basak, J. T. Eaton, C. E. Naylor, N. Justin, D. S. Moss, R. W. Titball, F. Nomura, M. Nagata, S. Ishjkawa, S. Takahashi, Kaoru Obuchi, Erich Staudegger, Manfred Kriechbaum, Robert I. Lehrer, Alan J. Waring, Karl Lohner, Susanne Gangl, Bernd Mayer, Gottfried Köhler, J. Shobini, Z. Guttenberg, B. Lortz, B. Hu, E. Sackmann, N. M. Kozlova, L. M. Lukyanenko, A. N. Antonovich, E. I. Slobozhanina, Andrey V. Krylov, Yuri N. Antonenko, Elena A. Kotova, Alexander A. Yaroslavov, Subhendu Ghosh, Amal K. Bera, Sudipto Das, Eva Urbánková, Masood Jelokhani-Niaraki, Karl Freeman, Petr Jezek, P. B. Usmanov, A. Ongarbaev, A. K. Tonkikh, Peter Pohl, Sapar M. Saparov, P. Harikumar, J. P. Reeves, S. Rao, S. K. Sikdar, A. S. Ghatpande, C. Corsso, A. C. Campos de Carvalho, W. A. Varanda, C. ElHamel, E. Dé, N. Saint, G. Molle, Anurae Varshney, M. K. Mathew, E. Loots, E. Y. Isacoff, Michiki Kasai, Naohiro Yamaguchi, Paramita Ghosh, Joseph Tigyi, Gabor Tigyi, Karoly Liliom, Ricardo Miledi, Maja R. Djurisic, Pavle R. Andjus, Indira H. Shrivastava, M. S. P. Sansom, C. Barrias, P. F. Oliveira, A. C. Mauricio, A. M. Rebelo da Costa, I. A. Lopes, S. V. Fedorovich, V. S. Chubanov, M. V. Sholukh, S. V. Konev, N. Fedirko, V. Manko, M. Klevets, N. Shvinka, B. S. Prabhananda, Mamata H. Kombrabail, S. Aravamudhan, Berenice Venegas-Cotero, Ivan Ortega Blake, Zhi-hong Zhang, Xiao-jian Hu, Han-qing Zhou, Wei-ying Cheng, Hang-fang Feng, L. O. Dubitsky, L. S. Vovkanvch, I. A. Zalyvsky, E. Savio-Galimberti, P. Bonazzola, J. E. Ponce-Homos, Mario Parisi, Claudia Capurro, Roxana Toriano, Laxma G. Ready, Larry R. Jones, David D. Thomas, B. A. Tashmukhamedov, B. T. Sagdullaev, D. Heitzmann, R. Warth, M. Bleich, R. Greger, K. T. G. Ferreira, H. G. Ferreira, Orna Zagoory, Essa Alfahel, Abraham H. Parola, Zvi Priel, H. Hama-Inaba, R. Wang, K. Choi, T. Nakajima, K. Haginoya, M. Mori, H. Ohyama, O. Yukawa, I. Hayata, Nanda B. Joshi, Sridhar K. Kannurpatti, Preeti G. Joshi, Mau Sinha, Xun Shen, Tianhui Hu, Ling Bei, Menno L. W. Knetsch, Nicole Schäfers, John Sandblom, Juris Galvanovskis, Roxana Pologea-Moraru, Eugenia Kovacs, Alexandra Dinu, S. H. Sanghvi, V. Jazbinšek, G. Thiel, W. Müller, G. Wübeller, Z. Tronteli, Leš Fajmut, Marko Marhl, Milan Brumen, I. D. Volotovski, S. G. Sokolovski, M. R. Knight, Alexei N. Vasil’ev, Alexander V. Chalyi, P. Sharma, P. J. Steinbach, M. Sharma, N. D. Amin, J. Barchir, R. W. Albers, H. C. Pant, M. Balasubramanyam, M. Condrescu, J. P. Gardner, Shamci Monajembashi, Gotz Pilarczyk, K. O. Greulich, F. M. El-Refaei, M. M. Talaat, A. I. El-Awadi, F. M. Ali, Ivan Tahradník, Jana Pavelková, Alexandra Zahradniková, Boris S. Zhorov, Vettai S. Ananthanaravanan, M. Ch. Michailov, E. Neu, W. Seidenbusch, E. Gornik, D. Martin, U. Welscher, D. G. Weiss, B. R. Pattnaik, A. Jellali, V. Forster, D. Hicks, J. Sahel, H. Dreyfus, S. Picaud, Hong-Wei Wang, Sen-fang Sui, Pradeep K. Luther, John Barry, Ed Morris, John Squire, C. Sivakama Sundari, D. Balasubramanian, K. Veluraia, T. Hema Thanka Christlet, M. Xavier Suresh, V. Laretta-Garde, Dubravka Krilov, Nataša Stojanović, Janko N. Herak, Ravi Jasuja, Maria Ivanova, Rossen Mirchev, Frank A. Ferrone, David Stopar, Ruud B. Spruijt, Cor J. A. M. Wolfs, Marcus A. Hemminga, G. Arcovito, M. De Spirito, Rajendra K. Agrawal, Amy B. Heagle, Pawel Penczek, Robert Grassucci, Joachim Frank, Manjuli R. Sharma, Loice H. Jeyakumar, Sidney Fleischer, Terence Wagenknecht, Carlo Knupp, Peter M. G. Munro, Eric Ezra, John M. Squire, Koji Ichihara, Hidefumi Kitazawa, Yusuke Iguchi, Tomohiko J. Itoh, Greta Pifat, Marina Kveder, Slavko Pečar, Milan Schara, Deepak Nair, Kavita Singh, Kanury V. S. Rao, Kanwaljeet Kaur, Deepti Jain, B. Sundaravadivel, Manisha Goel, D. M. Salunke, E. I. Kovalenko, G. N. Semenkova, S. N. Cherenkevich, T. Lakshmanan, D. Sriram, S. Srinivasan, D. Loganathan, T. S. Ramalingam, J. A. Lebrón, P. J. Bjorkman, A. K. Singh, T. N. Gayatri, Ernesto R. Caffarena, J. Raul Grigera, Paulo M. Bisch, V. Kiessling, P. Fromherz, K. N. Rao, S. M. Gaikwad, M. I. Khan, C. G. Suresh, P. Kaliannan, M. Elanthiraiyan, K. Chadha, J. Payne, J. L. Ambrus, M. P. N. Nair, Madhavan P. N. Nair, S. Mahajan, K. C. Chadha, R. Hewitt, S. A. Schwartz, J. Bourguignon, M. Faure, C. Cohen-Addad, M. Neuburger, R. Ober, L. Sieker, D. Macherel, R. Douce, D. S. Gurumurthy, S. Velmurugan, Z. Lobo, Ratna S. Phadke, Prashant Desai, I. M. Guseinova, S. Yu. Suleimanov, I. S. Zulfugarov, S. N. Novruzova, J. A. Aliev, M. A. Ismayilov, T. V. Savchenko, D. R. Alieva, Petr Ilík, Roman Kouřil, Hana Bartošková, Jan Nauš, Jvoti U. Gaikwad, Sarah Thomas, P. B. Vidyasagar, G. Garab, I. Simidjiev, S. Rajagopal, Zs. Várkonyi, S. Stoylova, Z. Cseh, E. Papp, L. Mustárdy, A. Holzenburg, R. Bruder, U. K. Genick, T. T. Woo, D. P. Millar, K. Gerwert, E. D. Getzoff, Tamás Jávorfí, Győző Garab, K. Razi Naqvi, Md. Kalimullah, Jyoti Gaikwad, Manoj Semwal, Roman Kouril, Petr Ilik, Man Naus, István Pomozi, Gábor Horváth, Rüdiger Wehner, Gary D. Bernard, Ana Damjanović, Thorsten Ritz, Klaus Schulten, Wang Jushuo, Shan Jixiu, Gong Yandao, Kuang Tingyun, Zhao Nanming, Arvi Freiberg, Kõu Timpmann, Rein Ruus, Neal W. Woodbury, E. V. Nemtseva, N. S. Kudryasheva, A. G. Sizykh, V. N. Shikhov, T. V. Nesterenko, A. A. Tikhomirov, Giorgio Forti, Giovanni Finazzi, Alberto Furia, Romina Paola Barbagallo, S. Iskenderova, R. Agalarov, R. Gasanov, Miyashita Osamu, G. O. Nobuhiro, R. K. Soni, M. Ramrakhiani, Hiromasa Yagi, Kacko Tozawa, Nobuaki Sekino, Tomoyuki Iwabuchi, Masasuke Yoshida, Hideo Akutsu, A. V. Avetisyan, A. D. Kaulen, V. P. Skulachev, B. A. Feniouk, Cécile Breyton, Werner Kühlbrandt, Maria Assarsson, Astrid Gräslund, G. Horváth, B. Libisch, Z. Gombos, N. V. Budagovskaya, N. Kudryasheva, Erisa Harada, Yuki Fukuoka, Tomoaki Ohmura, Arima Fukunishi, Gota Kawai, Kimitsuna Watanabe, Jure Derganc, Bojan Božič, Saša Svetina, Boštjan Žekš, J. F. Y. Hoh, Z. B. Li, G. H. Rossmanith, E. L. de Beer, B. W. Treijtel, P. L. T. M. Frederix, T. Blangè, S. Hénon, F. Galtet, V. Laurent, E. Planus, D. Isabey, L. S. Rath, P. K. Dash, M. K. Raval, C. Ramakrishnan, R. Balaram, Milan Randic, Subhash C. Basak, Marjan Vracko, Ashesh Nandy, Dragan Amic, Drago Beslo, Sonja Nikolic, Nenad Trinajstic, J. Walahaw, Marc F. J. Lensink, Boojala V. B. Reddy, Ilya N. Shindylov, Philip E. Bourne, M. C. Donnamaria, J. de Xammar Oro, J. R. Grigera, Monica Neagu, Adrian Neagu, Matej Praprotnik, Dušanka Janežič, Pekka Mark, Lennart Nilsson, L. La Fata, Laurent E. Dardenne, Araken S. Werneck, Marçal de O. Neto, N. Kannan, S. Vishveshwara, K. Veluraja, Gregory D. Grunwald, Alexandra T. Balaban, Kanika Basak, Brian D. Gute, Denise Mills, David Opitz, Krishnan Balasubramanian, G. I. Mihalas, Diana Lungeanu, G. Macovievici, Raluca Gruia, C. Cortez-Maghelly, B. Dalcin, E. P. Passos, S. Blesic, M. Ljubisavljevic, S. Milosevic, D. J. Stratimirovic, Nandita Bachhawat, Shekhar C. Mande, A. Nandy, Ayumu Saito, Koichi Nishigaki, Mohammed Naimuddin, Takatsugu Hirokawa, Mitsuo Ono, Hirotomo Takaesu, M. I. El Gohary, Abdalla S. Ahmed, A. M. Eissa, Hiroshi Nakashima, G. P. S. Raghava, N. Kurgalvuk, O. Goryn, Bernard S. Gerstman, E. V. Gritsenko, N. N. Remmel, O. M. Maznyak, V. A. Kratasyuk, E. N. Esimbekova, D. Tchitchkan, S. Koulchitsky, A. Tikhonov, A. German, Y. Pesotskaya, S. Pashkevich, S. Pletnev, V. Kulchitsky, Umamaheswar Duvvuri, Sridhar Charagundla, Rahim Rizi, John S. Leigh, Ravinder Reddy, Mahesh Kumar, O. Coshic, P. K. Julka, O. K. Rath, NR. Jagannathan, Karina Roxana Iliescu, Maria Sajin, Nicolcta Moisoi, Ileana Petcu, A. I. Kuzmenko, R. P. Morozova, I. A. Nikolenko, G. V. Donchenko, M. K. Rahman, M. M. Ahmed, Takehiro Watanabe, Y. Rubin, H. Gilboa, R. Sharony, R. Ammar, G. Uretzky, M. Khubchandani, H. N. Mallick, V. Mohan Kumar, Arijitt Borthakur, Erik M. Shapiro, M. Gulnaz Begum, Mahaveer N. Degaonkar, S. Govindasamy, Ivan Dimitrov, T. A. Kumosani, W. Bild, I. Stefanescu, G. Titescu, R. Iliescu, C. Lupusoru, V. Nastasa, I. Haulica, Gopal Khetawat, N. Faraday, M. Nealen, S. Noga, P. F. Bray, T. V. Ananieva, E. A. Lycholat, MV. Kosevich, S. G. Stepanyan, S. V. Antonyuk, R. Khachatryan, H. Arakelian, A. Kumar, S. Ayrapetyan, V. Mkheyan, S. Agadjanyan, A. Khachatryan, S. S. Rajan, V. Kabaleeswaran, Geetha Gopalakrishnan, T. R. Govindachari, Meera Ramrakhiani, Phillip Lowe, Andrew Badley, David C. Cullen, H. Hermel, W. Schmahl, H. Möhwald, Nirmalya Majumdar, Joydip Das, András Dér, Loránd Kelemen, László Oroszi, András Hámori, Jeremy J. Ramsden, Pál Ormos, D. Savitri, Chanchal K. Mitra, Toshio Yanagida, Seiji Esaki, Yuji Kimura, Tomoyuki Nishida, Yosiyuki Sowa, M. Radu, V. K. Koltover, Ya. I. Estrin, L. A. Kasumova, V. P. Bubnov, E. E. Laukhina, Rajiv Dotta, M. Degaonkar, P. Raghunathan, Rama Jayasundar, Pavel Novák, Milan Marko, Ivan Zahradník, Hiroaki Hirata, Hidetake Miyata, J. Balaji, P. Sengupta, S. Maiti, M. Gonsalves, A. L. Barker, J. V. Macpherson, D. O’Hare, C. P. Winlove, P. R. Unwin, R. Phillip, S. Banerjee, G. Ravindra Kumar, K. Nagayaka, R. Danev, S. Sugitani, K. Murata, Michael Gősch, H. Blom, P. Thyberg, Z. Földes-Papp, G. Björk, J. Holm, T. Heino, Masashi Yokochi, Fuyuhiko Inagaki, Masami Kusunoki, E. K. Matthews, J. Pines, Yu. P. Chukova, Vitaly K. Koltover, Geetanjali Bansal, Uma Singh, M. P. Bansal, Kotoko Nakata, Tastuya Nakano, Tsuguchika Kaminuma, B. P. S. Kang, U. Singh, Bonn Kirn, Neja Potocnik, Vito Stare, Latal Shukla, V. Natarajan, T. P. A. Devasagayam, M. D. Sastry, P. C. Kesavan, R. Sayfutdinov, V. V. Adamovich, D. Yu. Rogozin, A. G. Degermendzhy, C. L. Khetrapal, G. A. Nagana Gowda, Kedar Nath Ghimire, Ishida Masaru, H. Fujita, S. Ishiwata, Y. Kishimoto, S. Kawahara, M. Suzuki, H. Mori, M. Mishina, Y. Kirino, H. Ohshima, A. S. Dukhin, V. N. Shilov, P. J. Goetz, and R. K. Mishra

Subjects
0303 health sciences, biology, General Medicine, 010402 general chemistry, 01 natural sciences, Horseradish peroxidase, General Biochemistry, Genetics and Molecular Biology, 0104 chemical sciences, 03 medical and health sciences, Biochemistry, Manganese porphyrin, biology.protein, Enzyme reconstitution, General Agricultural and Biological Sciences, 030304 developmental biology
Published
1999
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5. Binding Mode of [Ruthenium(II) (1,10-Phenanthroline)2L]2+ with Poly(dT*dA-dT) Triplex. Ligand Size Effect on Third-Strand Stabilization

Author

Seog K. Kim, Per Lincoln, Eimer Tuite, Sang-Doh Choi, Bengt Nordén, and Myoung-Sun Kim

Subjects
Steric effects, Circular dichroism, Molecular Structure, Ligand, Stereochemistry, Circular Dichroism, Phenanthroline, Phenazine, Intercalation (chemistry), Molecular Conformation, Temperature, chemistry.chemical_element, DNA, Nucleic Acid Denaturation, Linear dichroism, Biochemistry, Ruthenium, chemistry.chemical_compound, Crystallography, Oligodeoxyribonucleotides, chemistry, Spectrophotometry, Nucleic Acid Conformation, Ruthenium Compounds, Phenanthrolines
Abstract

The binding of homochiral [Ru(II)(1,10-phenanthroline)(2)L](2+) complexes {where L = 1,10-phenanthroline (phen), dipyrido[3,2-a:2',3'-c]phenazine (DPPZ) or benzodipyrido[3,2-a:2',3'-c]phenazine (BDPPZ)} to poly(dT*dA-dT) triplex has been investigated by linear and circular dichroism and thermal denaturation. Analysis of the linear dichroism spectra indicates that the extended DPPZ and BDPPZ ligands lie approximately parallel to the base-pair and base-tripler planes consistent with intercalation which is also supported by strong hypochromism in the interligand absorption bands with either duplex or tripler. The spectral properties of any of the metal complex enantiomers were similar for binding to either duplex or tripler DNA, indicating that the third strand, which occupies the major groove of the template duplex, has little effect on the binding geometries and hence supports the hypothesis that the metal complexes all bind from the minor groove with the DPPZ and BDPPZ ligands intercalated but without intercalation in the case of [Ru(phen)(3)](2+). Third-strand stabilization depended on the nature of the third substituted phenanthroline chelate ligand but was not directly related to its size, with stabilizing power increasing in the order phen < BDPPZ < DPPZ. This observation further supports intercalation of the extended ligands from the minor groove of the tripler since the extended BDPPZ ligand that would protrude into the major groove of the template would have greater steric interference than DPPZ with the third DNA strand.

Published
1997
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6. Effects of Intercalators on Complexation of RecA with Duplex DNA

Author

Masayuki Takahashi, Eimer Tuite, Seog K. Kim, and Bengt Nordén

Subjects
Circular dichroism, Light, Ultraviolet Rays, Base pair, Plasma protein binding, medicine.disease_cause, Biochemistry, Structure-Activity Relationship, chemistry.chemical_compound, medicine, Nucleotide, Escherichia coli, chemistry.chemical_classification, Spectrum Analysis, DNA, biochemical phenomena, metabolism, and nutrition, Intercalating Agents, DNA-Binding Proteins, Rec A Recombinases, Crystallography, chemistry, Acridine, Nucleic acid, Biophysics, Acridines, Nucleic Acid Conformation, bacteria, Protein Binding
Abstract

To elucidate the binding mode of recombination protein A (RecA) to double-stranded (ds) DNA, the effects on the RecA-DNA interaction of several mono- and bisintercalators of the acridine, phenanthridine, and cyanine classes have been investigated by linear dichroism spectroscopy. Simple monointercalators lacking side chains efficiently promoted the binding of RecA to dsDNA in the absence of nucleotide cofactor, which is otherwise required. Bisintercalators varied in their ability to induce RecA binding, while monointercalators with aminoalkyl side chains proved inefficient. Modification of DNA structure by the intercalator appears to be necessary for induction of RecA binding, but if the intercalator has a bulky minor-groove-binding side chain, it does not induce RecA binding. In detailed studies with acridines, neither the binding geometry of intercalators nor the structure of DNA was significantly modified upon binding of RecA without cofactor. Judged by circular dichroism, similar RecA conformational changes accompanied bis-9-aminoacridine- and ATP gamma S-induced RecA association with DNA. In the presence of ATP gamma S, the intercalators inhibited the rate of RecA binding to dsDNA and were extruded from DNA upon binding of RecA. This competitive aspect may suggest that intercalation of some amino acid residue(s) plays a role in nucleotide-induced RecA binding. The stoichiometry of the RecA-DNA-intercalator filament was determined; in the fully formed filament the base pair:intercalator ratio is 2, and the base pair:RecA ratio also 2. This contrasts with a base pair:RecA ratio of 3 in the ATP gamma S-induced filament, although in both cases the DNA experiences 50% extension.

Published
1995
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7. Intercalative interactions of ethidium dyes with triplex structures

Author

Bengt Nordén and Eimer Tuite

Subjects
Circular dichroism, Poly T, Dimer, Clinical Biochemistry, Pharmaceutical Science, Nucleic Acid Denaturation, Linear dichroism, Biochemistry, chemistry.chemical_compound, Ethidium, Drug Discovery, Organic chemistry, Propidium iodide, Molecular Biology, Molecular Structure, Phenanthridine, Circular Dichroism, Organic Chemistry, Temperature, DNA, Intercalating Agents, Crystallography, chemistry, Duplex (building), Nucleic Acid Conformation, Molecular Medicine, Spectrophotometry, Ultraviolet, Ethidium homodimer assay, Poly A, Ethidium bromide, Propidium
Abstract

The binding of phenanthridine dyes to tripler poly(dT)*poly(dA). poly(dT) and its precursor duplex poly(dA). poly(dT) is characterized using linear dichroism and circular dichroism spectroscopy, and thermal denaturation. The two monomeric dyes ethidium bromide and propidium iodide are shown to behave similarly to each other in intercalating into and stabilizing both the duplex and the tripler structures. However, contrary to expectations, the extra cationic side-chain of propidium iodide provides no significant extra stabilization of tripler compared with ethidium bromide, although propidium does stabilize the duplex more than ethidium. The monomeric dyes appear to have somewhat different binding geometries with the duplex and tripler polymers. The dimeric dye ethidium homodimer is found to bis-intercalate in the tripler as well as the duplex but, in contrast to the monomers, no variation in geometry between duplex and tripler is observed. However, although dimer stabilizes the duplex, it has no effect on the thermal stability of the tripler. This lack of binding preferentiality of the dimer for tripler compared with the monomeric dyes indicates greater constraints on the accommodation of a bis-intercalator in the tripler structure than in the duplex.

Published
1995
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8. Sequence-Specific Interactions of Methylene Blue with Polynucleotides and DNA: A Spectroscopic Study

Author

Eimer Tuite and Bengt Nordén

Subjects
Circular dichroism, Chemistry, Stereochemistry, Intercalation (chemistry), General Chemistry, Dichroism, Linear dichroism, Biochemistry, Catalysis, chemistry.chemical_compound, Colloid and Surface Chemistry, Polynucleotide, Ionic strength, Binding site, Methylene blue
Abstract

The modes of binding of the phenothiazinium dye methylene blue (1) to alternating and nonalternating polynucleotides and to calf thymus (CT) DNA have been characterized using linear dichroism (LD) and circular dichroism (CD) spectroscopy. With the polynucleotide [poly(dG-dC)](2) the interaction at low binding ratios is shown to be purely intercalative and the binding mode is insensitive to changes in ionic strength. The observed CD spectrum is bisignate, which may be due to intercalation at the different base-pair steps (5'G-C3' and 5'C-G3'), giving rise to CD signals of different sign and shape, By contrast, a single intercalative binding mode with the alternating AT polynucleotide [poly(dA-dT)](2) is likely only at very low ionic strength; at high ionic strength (200 mM phosphate, pH 6.9), a second binding mode is also manifest which is attributed to groove binding of the dye. The absorption and linear dichroism spectroscopic features of the methylene blue/CT-DNA (42% GC) complex reflect those of complexes of the dye with both [poly(dA-dT)](2) and [poly(dG-dC)](2); the circular dichroism spectrum of the methylene blue/CT-DNA complex and its variation with ionic strength reflect the complexity of even this simple system where numerous possible binding sites exist. Comparative binding to the nonalternating polynucleotides poly(dA).poly(dT) and poly(da).poly(dC), which each possess only one base-pair step, was also examined. On the basis of the combined LD and CD evidence, it is proposed that the dye is loosely bound with poly(dA).poly(dT), probably in the major groove, and intercalated with poly(dG).poly(dC).

Published
1994
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9. New trends in photobiology

Author

Eimer Tuite and John M. Kelly

Subjects
chemistry.chemical_classification, Radiation, Radiological and Ultrasound Technology, Singlet oxygen, Guanine, Biophysics, Biological membrane, Photochemistry, Thionine, chemistry.chemical_compound, chemistry, Biochemistry, Nucleic acid, Radiology, Nuclear Medicine and imaging, Nucleotide, Methylene blue, DNA
Abstract

The light-induced reactions of methylene blue and related phenothiazinium dyes with biological substrates are described. The properties of the excited states of the dyes, their reactions with nucleic acids and their photosensitised chemical modifications of nucleic acid bases are examined. Reports on phenothiazinium dye-induced damage to proteins, lipids, biological membranes, organelles, viruses, bacteria, mammalian cells and carcinomas are reviewed.

Published
1993
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10. Dispersions of alkyl-capped silicon nanocrystals in aqueous media: photoluminescence and ageing

Author

Naif H. Alsharif, F. M. Dickinson, A. Houlton, Yimin Chao, Lidija Šiller, Benjamin R. Horrocks, HK Datta, Eimer Tuite, Christine E. M. Berger, and T. A. Alsop

Subjects
Flocculation, Silicon, Photoluminescence, Luminescence, Time Factors, Inorganic chemistry, chemistry.chemical_element, Ether, Biochemistry, Analytical Chemistry, chemistry.chemical_compound, Quantum Dots, Electrochemistry, Environmental Chemistry, Humans, Nanotechnology, Polymethyl Methacrylate, Dimethyl Sulfoxide, Furans, Spectroscopy, Tetrahydrofuran, Alkyl, chemistry.chemical_classification, Spectrometry, Fluorescence, Nanocrystal, chemistry, Solvents, HeLa Cells
Abstract

Alkyl-capped silicon nanocrystals can be dispersed in aqueous media by shaking or stirring their solutions in organic solvents (DMSO, ether, THF) with excess water. THF is the most straightforward choice with which to prepare stable aqueous dispersions, because the nanocrystals are very soluble in THF and it is also miscible with water. As little as 0.01% v/v tetrahydrofuran is sufficient. DMSO and ether were the preferred choices for subsequent staining of live cells because THF shows some acute toxicity even when very dilute. The luminescence intensity of the aqueous dispersions is linear in particle concentration and independent of pH over the range 5–9. The sols retain their photoluminescence and are stable against flocculation for at least 6 months.

Published
2008

11. Photobleaching of asymmetric cyanines used for fluorescence imaging of single DNA molecules

Author

Eimer Tuite, and Björn Åkerman, and Claire Kanony

Subjects
Models, Molecular, Fluorescence-lifetime imaging microscopy, Magnetic Resonance Spectroscopy, Time Factors, Thymus Gland, Photochemistry, Biochemistry, Coliphages, Catalysis, Fluorescence spectroscopy, chemistry.chemical_compound, Colloid and Surface Chemistry, Fluorescence microscope, Animals, Cyanine, Photodegradation, Fluorescent Dyes, Electrophoresis, Agar Gel, Benzoxazoles, Quenching (fluorescence), Photolysis, Deoxyadenosines, Molecular Structure, Quinolinium Compounds, Spectrum Analysis, Dose-Response Relationship, Radiation, General Chemistry, DNA, Photobleaching, Fluorescence, Spectrometry, Fluorescence, chemistry, Microscopy, Fluorescence, Cattle, Oxidation-Reduction
Abstract

The photobleaching of the cyanine dyes YO and YOYO has been investigated for both free and DNA-bound dyes, using absorption and fluorescence spectroscopy coupled with fluorescence microscopy. For the free dyes, the nature of the reactive species involved in the photodegradation process is different for the monomer and the dimer, as shown by scavenger studies. For DNA-bound dyes, photoinduced fading of the visible absorption band occurs by different pathways depending on the drug binding mode and can be attenuated by appropriate scavengers. However, none of these scavengers were found to have any significant effect on the photobleaching of dye fluorescence. It appears that the reduction of fluorescence intensity comes from a quenching of the dye fluorescence by modified DNA bases, possibly 8-oxo-7,8-dihydro-2‘-deoxyguanosine.

Published
2001

12. Ultrafast electron-transfer reactions between thionine and guanosine bases

Author

Godfrey S. Beddard, John M. Kelly, Douglas J. Whittaker, Gavin D. Reid, Mark Day, Eimer Tuite, and Caitriona M. Creely

Subjects
Electron transfer reactions, Guanosine, Chemistry, General Chemistry, DNA, Photochemistry, Biochemistry, Catalysis, Thionine, Electron Transport, chemistry.chemical_compound, Colloid and Surface Chemistry, Phenothiazines, Ultrashort pulse
Published
2001

13. Thermodynamics of sequence-specific binding of PNA to DNA

Author

Peter E. Nielsen, Tommi Ratilainen, Anders Holmén, Bengt Nordén, and Eimer Tuite

Subjects
Peptide Nucleic Acids, Circular dichroism, Base Pair Mismatch, Ultraviolet Rays, Circular Dichroism, Entropy, Thermodynamics, Nucleic Acid Hybridization, Isothermal titration calorimetry, Calorimetry, DNA, Biochemistry, Binding constant, Crystallography, chemistry.chemical_compound, Nucleic acid thermodynamics, chemistry, Nucleic acid, Energy Metabolism
Abstract

For further characterization of the hybridization properties of peptide nucleic acids (PNAs), the thermodynamics of hybridization of mixed sequence PNA-DNA duplexes have been studied. We have characterized the binding of PNA to DNA in terms of binding affinity (perfectly matched duplexes) and sequence specificity of binding (singly mismatched duplexes) using mainly absorption hypochromicity melting curves and isothermal titration calorimetry. For perfectly sequence-matched duplexes of varying lengths (6-20 bp), the average free energy of binding (DeltaG degrees ) was determined to be -6.5+/-0.3 kJ mol(-1) bp(-1), corresponding to a microscopic binding constant of about 14 M(-1) bp(-1). A variety of single mismatches were introduced in 9- and 12-mer PNA-DNA duplexes. Melting temperatures (T(m)) of 9- and 12-mer PNA-DNA duplexes with a single mismatch dropped typically 15-20 degrees C relative to that of the perfectly matched sequence with a corresponding free energy penalty of about 15 kJ mol(-1) bp(-1). The average cost of a single mismatch is therefore estimated to be on the order of or larger than the gain of two matched base pairs, resulting in an apparent binding constant of only 0.02 M(-1) per mismatch. The impact of a mismatch was found to be dependent on the neighboring base pairs. To a first approximation, increasing the stability of the surrounding region, i.e., the distribution of A.T and G.C base pairs, decreases the effect of the introduced mismatch.

Published
2000

14. Difference between active and inactive nucleotide cofactors in the effect on the DNA binding and the helical structure of RecA filament dissociation of RecA--DNA complex by inactive nucleotides

Author

Hye-Kyung Kim, Bengt Nordén, Tassadite Selmane, Masayuki Takahashi, Kell Mortensen, Eimer Tuite, and Christine Ellouze

Subjects
chemistry.chemical_classification, Circular dichroism, GTP', Oligonucleotide, Nucleotides, Circular Dichroism, Guanosine, DNA, biochemical phenomena, metabolism, and nutrition, Biochemistry, Protein filament, DNA-Binding Proteins, chemistry.chemical_compound, Rec A Recombinases, chemistry, Biophysics, bacteria, Nucleic Acid Conformation, Nucleotide, Homologous recombination, Protein Binding
Abstract

The RecA protein requires ATP or dATP for its coprotease and strand exchange activities. Other natural nucleotides, such as ADP, CTP, GTP, UTP and TTP, have little or no activation effect on RecA for these activities. We have investigated the activation mechanism, and the selectivity for ATP, by studying the effect of various nucleotides on the DNA binding and the helical structure of the RecA filament. The interaction with DNA was investigated via fluorescence measurements with a fluorescent DNA analog and fluorescein-labeled oligonucleotides, assisted by linear dichroism. Filament structure was investigated via small-angle neutron scattering. There is no simple correlation between filament elongation, DNA binding affinity of RecA, and DNA structure in the RecA complex. There may be multiple conformations of RecA, Both coprotease and strand exchange activities require formation of a rigid and well organized complex. The triphosphate nucleotides which do not activate RecA, destabilize the RecA-DNA complex, indicating that the chemical nature of the nucleotide nucleobase is very important for the stability of RecA-DNA complex. Higher stability of the RecA-DNA complex in the presence of adenosine 5'-O-3-thiotriphosphate or guanosine 5'-O-3-thiotriphosphate than ATP or GTP indicates that contact between the protein and the chemical group at the gamma position of the nucleotide also affects the stability of the RecA-DNA complex. This contact appears also important for the rigid organization of DNA because ADP strongly decreases the rigidity of the complex.

Published
1999

15. Hybridization of peptide nucleic acid

Author

Peter E. Nielsen, Leif Christensen, Bengt Nordén, Gerald Haaima, Tommi Ratilainen, Anders Holmén, and Eimer Tuite

Subjects
Models, Molecular, Circular dichroism, Stereochemistry, Biochemistry, Electron Transport, chemistry.chemical_compound, Fluorescein, Peptide nucleic acid, musculoskeletal, neural, and ocular physiology, Circular Dichroism, Nucleic Acid Heteroduplexes, Nucleic Acid Hybridization, Isothermal titration calorimetry, DNA, Fluorescence, Spectrometry, Fluorescence, chemistry, Oligodeoxyribonucleotides, Duplex (building), biological sciences, cardiovascular system, Thermodynamics, Peptides, tissues, Linker
Abstract

The thermodynamics of hybridization and the conformations of decameric mixed purine-pyrimidine sequence PNA/PNA, PNA/DNA, and DNA/DNA duplexes have been studied using fluorescence energy transfer (FET), absorption hypochromicity (ABS), isothermal titration calorimetry (ITC), and circular dichroism (CD) techniques. The interchromophoric distances determined in the FET experiments on fluorescein- and rhodamine-labeled duplexes indicate that the solution structures of the duplexes are extended helices in agreement with available NMR (PNA/DNA) and crystal X-ray data (PNA/PNA). The melting thermodynamics of the duplexes was studied with both FET and ABS. The thermodynamic parameters obtained with ABS are in good agreement with the parameters from calorimetric measurements while FET detection of duplex melting gives in most cases more favorable free energies of hybridization. This discrepancy between FET and ABS detection is ascribed to the conjugated dyes which affect the stability of the duplexes substantially. Especially, the dianionic fluorescein attached via a flexible linker either to PNA or to DNA seems to be involved in an attractive interaction with the opposite dicationic lysine when hybridized to a PNA strand. This interaction leads to an increased thermal stability as manifested as a 3-4 degrees C increase of the melting temperature. For the PNA/DNA duplex where fluorescein is attached to the PNA strand, a large destabilization (Delta T-m = -12 degrees C) occurs relative to the unlabeled duplex, probably originating from electrostatic repulsion between the fluorescein and the negatively charged DNA backbone. In the case of the PNA/PNA duplex, the sense of helicity of the duplex is reversed upon conjugation of fluorescein via a flexible linker arm, but not when the fluorescein is attached without a linker to the PNA.

Published
1998

16. Nucleotide cofactor-dependent structural change of Xenopus laevis Rad51 protein filament detected by small-angle neutron scattering measurements in solution

Author

Kazuhiro Maeshima, Christine Ellouze, Kell Mortensen, Toshihiro Horii, Masayuki Takahashi, Eimer Tuite, Bengt Nordén, Hye-Kyung Kim, and Katsumi Morimatsu

Subjects
RAD51, Xenopus, Biology, Xenopus Proteins, Biochemistry, Protein Structure, Secondary, Protein filament, chemistry.chemical_compound, Xenopus laevis, Adenosine Triphosphate, ATP hydrolysis, Animals, Scattering, Radiation, Nucleotide, chemistry.chemical_classification, Neutrons, Adenine Nucleotides, Affinity Labels, DNA, biology.organism_classification, Small-angle neutron scattering, Adenosine Diphosphate, DNA-Binding Proteins, Solutions, Crystallography, chemistry, Rad51 Recombinase, Homologous recombination
Abstract

Rad51 protein, a eukaryotic homologue of RecA protein, forms a filamentous complex with DNA and catalyzes homologous recombination. We have analyzed the structure of Xenopus Rad51 protein (XRad51.1) in solution by small-angle neutron scattering (SANS). The measurements showed that XRad51.1 forms a helical filament independently of DNA. The sizes of the cross-sectional and helical pitch of the filament could be determined, respectively, from a Guinier plot and the position of the subsidiary maximum of SANS data. We observed that the helical structure is modified by nucleotide binding as in the case of RecA. Upon ATP binding under high-salt conditions (600 mM NaCl), the helical pitch of XRad51.1 filament was increased from 8 to 10 nm and the cross-sectional diameter decreased from 7 to 6 nm. The pitch sizes of XRad51.1 are similar to, though slightly larger than, those of RecA filament under corresponding conditions. A similar helical pitch size was observed by electron microscopy for budding yeast Rad51 [Ogawa, T., et al. (1993) Science 259, 1896-1899]. In contrast to the RecA filament, the structure of XRad51.1 filament with ADP is not significantly different from that with ATP. Thus, the hydrolysis of ATP to ADP does not modify the helical filament of XRad51.1. Together with our recent observation that ADP does not weaken the XRad51.1/DNA interaction, the effect of ATP hydrolysis on XRad51.1 nucleofilament should be very different from that on RecA.

Published
1997

17. Effects of minor and major groove-binding drugs and intercalators on the DNA association of minor groove-binding proteins RecA and deoxyribonuclease I detected by flow linear dichroism

Author

Masayuki Takahashi, Eimer Tuite, Per Hagmar, Ulrica Sehlstedt, and Bengt Nordén

Subjects
Circular dichroism, Indoles, Ultraviolet Rays, Plasma protein binding, Ligands, Biochemistry, DNA-binding protein, chemistry.chemical_compound, Methyl Green, Ethidium, Deoxyribonuclease I, Chemistry, Circular Dichroism, Spectrum Analysis, DNA, Ligand (biochemistry), Intercalating Agents, DNA binding site, DNA-Binding Proteins, Crystallography, Rec A Recombinases, Biophysics, Nucleic Acid Conformation, Ethidium bromide, Protein Binding
Abstract

Linear and circular dichroic spectroscopies have been employed to investigate the effects of small DNA ligands on the interactions of two proteins which bind to the minor groove of DNA, viz. RecA protein from Escherichia coli and deoxyribonuclease I (bovine pancreas). Ligands representing three specific non-covalent binding modes were investigated: 4',6-diamidino-2-phenylindole and distamycin A (minor groove binders), methyl green (major groove binder), and methylene blue, ethidium bromide and ethidium dimer (intercalators). Linear dichroism was demonstrated to be an excellent detector, in real time, of DNA double-strand cleavage by deoxyribonuclease I. Ligands bound in all three modes interfered with the deoxyribonuclease I digestion of dsDNA, although the level of interference varied in a manner which could be related to the ligand binding site, the ligand charge appearing to be less important. In particular, the retardation of deoxyribonuclease I cleavage by the major groove binder methyl green demonstrates that accessibility to the minor groove can be affected by occupancy of the opposite groove. Binding of all three types of ligand also had marked effects on the interaction of RecA with dsDNA in the presence of non-hydrolyzable cofactor adenosine 5'-O-3-thiotriphosphate, decreasing the association rate to varying extents but with the strongest effects from ligands having some minor groove occupancy. Finally, each ligand was displaced from its DNA binding site upon completion of RecA association, again demonstrating that modification of either groove can affect the properties and behaviour of the other. The conclusions are discussed against the background of previous work on the use of small DNA ligands to probe DNA-protein interactions.

Published
1997

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