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1. Efficient enzymatic synthesis of ampicillin by mutant Alcaligenes faecalis penicillin G acylase.

Author

Deng S, Su E, Ma X, Yang S, and Wei D

Subjects
Penicillin Amidase genetics, Alcaligenes faecalis enzymology, Ampicillin metabolism, Penicillin Amidase metabolism, Protein Engineering methods
Abstract

Semi-synthetic β-lactam antibiotics (SSBAs) are one of the most important antibiotic families in the world market. Their enzymatic synthesis can be catalyzed by penicillin G acylases (PGAs). In this study, to improve enzymatic synthesis of ampicillin, site-saturating mutagenesis was performed on three conserved amino acid residues: βF24, αR146, and αF147 of thermo-stable penicillin G acylase from Alcaligenes faecalis (Af PGA). Four mutants βF24G, βF24A, βF24S, and βF24P were recovered by screening the mutant bank. Kinetic analysis of them showed up to 800-fold increased kcat/Km value for activated acyl donor D-phenylglycine methyl ester (D-PGME). When βF24G was used for ampicillin synthesis under kinetic control at industrially relevant conditions, 95% of nucleophile 6-aminopenicillanic acid (6-APA) was converted to ampicillin in aqueous medium at room temperature while 12% process time is needed to reach maximum product accumulation at 25% enzyme concentration compared with the wild-type Af PGA. Consequently, process productivity of enzymatic synthesis of ampicillin catalyzed by Af PGA was improved by more than 130 times, which indicated an enzyme viable for efficient SSBAs synthesis., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Published
2015
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2. Engineering of a glycosidase Family 7 cellobiohydrolase to more alkaline pH optimum: the pH behaviour of Trichoderma reesei Cel7A and its E223S/ A224H/L225V/T226A/D262G mutant.

Author

Becker D, Braet C, Brumer H 3rd, Claeyssens M, Divne C, Fagerström BR, Harris M, Jones TA, Kleywegt GJ, Koivula A, Mahdi S, Piens K, Sinnott ML, Ståhlberg J, Teeri TT, Underwood M, and Wohlfahrt G

Subjects
Alkalies, Catalytic Domain genetics, Cellobiose analogs & derivatives, Cellulase chemistry, Cellulase genetics, Cellulose 1,4-beta-Cellobiosidase, Crystallography, X-Ray, Enzyme Stability, Hydrogen-Ion Concentration, Kinetics, Models, Molecular, Mutation, Trichoderma genetics, Cellulase metabolism, Cellulose metabolism, Histidine, Protein Engineering, Trichoderma enzymology
Abstract

The crystal structures of Family 7 glycohydrolases suggest that a histidine residue near the acid/base catalyst could account for the higher pH optimum of the Humicola insolens endoglucanase Cel7B, than the corresponding Trichoderma reesei enzymes. Modelling studies indicated that introduction of histidine at the homologous position in T. reesei Cel7A (Ala(224)) required additional changes to accommodate the bulkier histidine side chain. X-ray crystallography of the catalytic domain of the E223S/A224H/L225V/T226A/D262G mutant reveals that major differences from the wild-type are confined to the mutations themselves. The introduced histidine residue is in plane with its counterpart in H. insolens Cel7B, but is 1.0 A (=0.1 nm) closer to the acid/base Glu(217) residue, with a 3.1 A contact between N(epsilon2) and O(epsilon1). The pH variation of k(cat)/K(m) for 3,4-dinitrophenyl lactoside hydrolysis was accurately bell-shaped for both wild-type and mutant, with pK(1) shifting from 2.22+/-0.03 in the wild-type to 3.19+/-0.03 in the mutant, and pK(2) shifting from 5.99+/-0.02 to 6.78+/-0.02. With this poor substrate, the ionizations probably represent those of the free enzyme. The relative k(cat) for 2-chloro-4-nitrophenyl lactoside showed similar behaviour. The shift in the mutant pH optimum was associated with lower k(cat)/K(m) values for both lactosides and cellobiosides, and a marginally lower stability. However, k(cat) values for cellobiosides are higher for the mutant. This we attribute to reduced non-productive binding in the +1 and +2 subsites; inhibition by cellobiose is certainly relieved in the mutant. The weaker binding of cellobiose is due to the loss of two water-mediated hydrogen bonds.

Published
2001
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3. Characterization of Histone Deacetylase 8 (HDAC8) Selective Inhibition Reveals Specific Active Site Structural and Functional Determinants

Author

Jelena Melesina, Wolfgang Sippl, Tino Heimburg, Christophe Romier, Martin Marek, Karin Schmidtkunz, E. Ramos-Morales, Julien Lancelot, C. Da Veiga, Manfred Jung, Takayoshi Suzuki, Dina Robaa, Eric Ennifar, Dmitrii V. Kalinin, T.B. Shaik, Raymond J. Pierce, Alokta Chakrabarti, Ralph Holl, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Martin-Luther-Universität Halle Wittenberg (MLU), Albert-Ludwigs-Universität Freiburg, Centre d’Infection et d’Immunité de Lille - INSERM U 1019 - UMR 9017 - UMR 8204 (CIIL), Centre National de la Recherche Scientifique (CNRS)-Centre Hospitalier Régional Universitaire [Lille] (CHRU Lille)-Université de Lille-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut Pasteur de Lille, Réseau International des Instituts Pasteur (RIIP)-Réseau International des Instituts Pasteur (RIIP), Institut de biologie moléculaire et cellulaire (IBMC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), University of Münster, Kyoto Prefectural University of Medicine [Kyoto, Japon], Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), University of Hamburg, This work and the authors of this paper have been supported by funding from the European Union’s Seventh Framework Programme for research, technological development, and demonstration under grant agreements nos. 241865 (SEtTReND) and 602080 (A-ParaDDisE) as well as the German Research Foundation (DFG) to W.S. (Si868/13-1) and M.J. (Ju295/13-1). This study was supported by the grant ANR-10-LABX-0030-INRT, a French State fund managed by the Agence Nationale de la Recherche under the frame program Investissements d’Avenir ANR-10-IDEX-0002-02. C.R., M.M., T.B.S., E.R.M., and R.J.P. are supported by institutional funds from the Centre National de la Recherche Scientifique (CNRS), the Institut National de la Santé et de la Recherche Médicale (INSERM), the Université de Strasbourg, the Institut Pasteur de Lille and the Université de Lille. W.S. was supported by the European Regional Development Fund of the European Commission. We acknowledge the support and the use of resources of the French Infrastructure for Integrated Structural Biology FRISBI ANR-10-INBS-05 and of Instruct-ERIC, We thank members of the ESRF-EMBL joint structural biology groups, the SOLEIL, and the Swiss Light Source (SLS) synchrotrons for the use of their beamline facilities and for help during data collection. We are grateful to Alastair McEwen (IGBMC) for his kind assistance during X-ray data collections., ANR-10-IDEX-0002,UNISTRA,Par-delà les frontières, l'Université de Strasbourg(2010), ANR-10-INBS-0005,FRISBI,Infrastructure Française pour la Biologie Structurale Intégrée(2010), European Project: 241865,EC:FP7:HEALTH,FP7-HEALTH-2009-single-stage,SETTREND(2010), European Project: 602080,EC:FP7:HEALTH,FP7-HEALTH-2013-INNOVATION-1,A-PARADDISE(2014), Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institut Pasteur de Lille, Réseau International des Instituts Pasteur (RIIP)-Réseau International des Instituts Pasteur (RIIP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Lille-Centre Hospitalier Régional Universitaire [Lille] (CHRU Lille)-Centre National de la Recherche Scientifique (CNRS), and Westfälische Wilhelms-Universität Münster = University of Münster (WWU)

Subjects
0301 basic medicine, Indoles, [SDV]Life Sciences [q-bio], Molecular Dynamics Simulation, Hydroxamic Acids, Isozyme, Histone Deacetylases, Substrate Specificity, 03 medical and health sciences, Structure-Activity Relationship, 0302 clinical medicine, Catalytic Domain, Drug Discovery, Hydrolase, Humans, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Epigenetics, Amino Acid Sequence, Tyrosine, biology, Chemistry, Active site, HDAC8, Protein engineering, Triazoles, 3. Good health, Cell biology, Histone Deacetylase Inhibitors, Repressor Proteins, 030104 developmental biology, Histone, 030220 oncology & carcinogenesis, biology.protein, Molecular Medicine
Abstract

International audience; Metal-dependent histone deacetylases (HDACs) are key epigenetic regulators that represent promising therapeutic targets for the treatment of numerous human diseases. Yet the currently FDA-approved HDAC inhibitors nonspecifically target at least several of the 11 structurally similar but functionally different HDAC isozymes, which hampers their broad usage in clinical settings. Selective inhibitors targeting single HDAC isozymes are being developed, but precise understanding in molecular terms of their selectivity remains sparse. Here, we show that HDAC8-selective inhibitors adopt a L-shaped conformation required for their binding to a HDAC8-specific pocket formed by HDAC8 catalytic tyrosine and HDAC8 L1 and L6 loops. In other HDAC isozymes, a L1–L6 lock sterically prevents L-shaped inhibitor binding. Shielding of the HDAC8-specific pocket by protein engineering decreases potency of HDAC8-selective inhibitors and affects catalytic activity. Collectively, our results unravel key HDAC8 active site structural and functional determinants important for the design of next-generation chemical probes and epigenetic drugs.

Published
2018