Search

Your search keyword '"Jayaraman, Vasanthi"' showing total 278 results
Start Over Author "Jayaraman, Vasanthi" Publication Type Academic Journals
278 results on '"Jayaraman, Vasanthi"'

4. Partial agonism in heteromeric GLUK2/GLUK5 kainate receptor.

Author

Paudyal, Nabina, Das, Anindita, Carrillo, Elisa, Berka, Vladimir, and Jayaraman, Vasanthi

Abstract

Kainate receptors are a subtype of ionotropic glutamate receptors that form transmembrane channels upon binding glutamate. Here, we have investigated the mechanism of partial agonism in heteromeric GluK2/K5 receptors, where the GluK2 and GluK5 subunits have distinct agonist binding profiles. Using single‐molecule Förster resonance energy transfer, we found that at the bi‐lobed agonist‐binding domain, the partial agonist AMPA‐bound receptor occupied intermediate cleft closure conformational states at the GluK2 cleft, compared to the more open cleft conformations in apo form and more closed cleft conformations in the full agonist glutamate‐bound form. In contrast, there is no significant difference in cleft closure states at the GluK5 agonist‐binding domain between the partial agonist AMPA‐ and full agonist glutamate‐bound states. Additionally, unlike the glutamate‐bound state, the dimer interface at the agonist‐binding domain is not decoupled in the AMPA‐bound state. Our findings suggest that partial agonism observed with AMPA binding is mediated primarily due to differences in the GluK2 subunit, highlighting the distinct contributions of the subunits towards activation. [ABSTRACT FROM AUTHOR]

Published
2025
Full Text
View/download PDF

6. Structure, Function, and Pharmacology of Glutamate Receptor Ion Channels

Author

Hansen, Kasper B., Wollmuth, Lonnie P., Bowie, Derek, Furukawa, Hiro, Menniti, Frank S., Sobolevsky, Alexander I., Swanson, Geoffrey T., Swanger, Sharon A., Greger, Ingo H., Nakagawa, Terunaga, McBain, Chris J., Jayaraman, Vasanthi, Low, Chian-Ming, Dell’Acqua, Mark L., Diamond, Jeffrey S., Camp, Chad R., Perszyk, Riley E., Yuan, Hongjie, and Traynelis, Stephen F.

Published
2021
Full Text
View/download PDF

32. Ca2+ efflux facilitated by co-transport of inorganic phosphate anion in the H+/Ca2+ antiporter YfkE.

Author

Niu, Wei, Zhou, Wenchang, Lu, Shuo, Vu, Trung, Jayaraman, Vasanthi, Faraldo-Gómez, José D., and Zheng, Lei

Subjects
PHOSPHATES, ANIONS, BINDING sites
Abstract

Ca2+ is an important signaling messenger. In microorganisms, fungi, and plants, H+/Ca2+ antiporters (CAX) are known to play key roles in the homeostasis of intracellular Ca2+ by catalyzing its efflux across the cell membrane. Here, we reveal that the bacterial CAX homolog YfkE transports Ca2+ in two distinct modes: a low-flux H+/Ca2+ exchange mode and a high-flux mode in which Ca2+ and phosphate ions are co-transported (1:1) in exchange for H+. Coupling with phosphate greatly accelerates the Ca2+ efflux activity of YfkE. Our studies reveal that Ca2+ and phosphate bind to adjacent sites in a central translocation pathway and lead to mechanistic insights that explain how this CAX alters its conserved alpha-repeat motifs to adopt phosphate as a specific "transport chaperon" for Ca2+ translocation. This finding uncovers a co-transport mechanism within the CAX family that indicates this class of proteins contributes to the cellular homeostasis of both Ca2+ and phosphate. Bacterial CAX antiporter homolog YfkE can transport Ca2+ and inorganic phosphate (Pi) together in a 1:1 ratio, exchanging them for H+ and becoming a high-flux antiporter when coupled with Pi. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

40. Stereochemistry of glutamate receptor agonist efficacy: Engineering a dual-specificity AMPA/kainate receptor

Author

Madden, Dean R., Cheng, Qing, Jayaraman, Vasanthi, Thirna, Shalita, Zimmermann, Herbert, Rajan, Shanti, Reinelt, Stefan, Rigo, Frnak, and Keinanen, Kari

Subjects
Glutamate -- Chemical properties, Stereochemistry -- Research, Biological sciences, Chemistry
Abstract

An attempt is made to show that structure-based mutation L651V converts the GluR4 AMPA receptor into a dual-specificity AMPA/kinate receptor fully activated by both agonists. Further, the correlation between agonist efficacy and a series of vibrational and fluorescence spectroscopic signals of agonist binding to the corresponding wild-type and mutant GluR4 ligand-binding domains is investigated.

Published
2004

41. A vibrational spectroscopic investigation of interactions of agonists with GluR0 a prokaryotic glutamate receptor

Author

Cheng, Qing, Thiran, Shalita, Yernool, Dinesh, Gouaux, Eric, and Jayaraman, Vasanthi

Subjects
Biochemistry -- Research, Glutamate -- Physiological aspects, Prokaryotes -- Physiological aspects, Ligands -- Physiological aspects, Serine -- Physiological aspects, Glutamine -- Physiological aspects, Biological sciences, Chemistry
Abstract

Research has been conducted on the carboxylate groups of the ligands, glytamate, serine and glutamine. The interactions of these groups with the ligand-binding domain of the prokaryotic ionotropic glutamate receptor have been investigated via the use of Fourier transform infrared spectroscopy and the results are reported.

Published
2002

42. Ligand-protein interactions in the glutamate receptor

Author

Jayaraman, Vasanthi and Madden, Dean R.

Subjects
Biochemistry -- Research, Fourier transform infrared spectroscopy -- Usage, Ligand binding (Biochemistry) -- Research, Glutamate -- Physiological aspects, Biological sciences, Chemistry
Abstract

A Fourier transform infrared (FTIR) spectroscopy study has found chemical/structural differences that may explain the different functional characteristics of the two agonists that act on ionotropic glutamate receptors. The results of the study complement and extend recent crystallographic structures of the ligand-binding domain. Glutamate binding brings on more extensive secondary structural changes in the ligand-binding domain than kainate binding does and changes the hydrogen bonding strength of the single free cysteine side chain in the domain unlike kainate. The interaction of the binding site arginine residue with kainate seems to be stronger than with glutamate.

Published
2000

45. Synthesis and photochemistry of a photolabile precursor of N-methyl-D-aspartate (NMDA) that is photolyzed in the microsecond time region and is suitable for chemical kinetic investigations of the NMDA receptor

Author

Gee, Kyle R., Niu, Li, Schaper, Klaus, Jayaraman, Vasanthi, and Hess, George P.

Subjects
Methyl aspartate -- Research, Proteins -- Receptors, Biological sciences, Chemistry
Abstract

The synthesis and characterization of the caged N-methyl-D-aspartic acid beta-(2,2'-dinitrobenzhydryl)-ligand (DNB) NMDA are presented. In this NMDA precursor, the carboxylate side chain was protected as a photosensitive 2,2'-dinitrobenzhydryl ester. Photolysis with 208 nm laser light generated the free NMDA with a time constant of 4.2 +/- 0.1 microseconds at pH7 and a photolysis quantum yield of 0.18 +/- 0.05. The reaction conditions and mechanisms for the synthesis are discussed.

Published
1999

48. Channel-opening mechanism of a kainate-activated glutamate receptor: kinetic investigations using a laser-pulse photolysis technique

Author

Jayaraman, Vasanthi

Subjects
Ligands (Biochemistry) -- Physiological aspects, Neurotoxic agents -- Physiological aspects, Rats as laboratory animals -- Physiological aspects, Biological sciences, Chemistry
Abstract

A study relating to the investigation of the neurotoxin or excitatory ligand called kainate was conducted to determine the intrinsic dissociation constant of kainate, the channel opening equilibrium constant and the rate constants for channel opening and closing of the kainate activated glutamate receptor in rat hippocampal neurons using fast kinetic techniques such as the rapid flow method (cell flow) with a 10 ms time resolution and laser pulse photolysis techniques at a particular time resolution. Results of the study are discussed.

Published
1998

Catalog

Books, media, physical & digital resources
See catalog results