1
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Cardwell PA, Del Moro C, Murphy MP, Lapthorn AJ, Hartley RC. Human mitochondrial glutathione transferases: Kinetic parameters and accommodation of a mitochondria-targeting group in substrates. Bioorg Med Chem 2024; 104:117712. [PMID: 38593670 DOI: 10.1016/j.bmc.2024.117712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 04/01/2024] [Accepted: 04/01/2024] [Indexed: 04/11/2024]
Abstract
Glutathione-S-transferases are key to the cellular detoxification of xenobiotics and products of oxidative damage. GSTs catalyse the reaction of glutathione (GSH) with electrophiles to form stable thioether adducts. GSTK1-1 is the main GST isoform in the mitochondrial matrix, but the GSTA1-1 and GSTA4-4 isoforms are also thought to be in the mitochondria with their distribution altering in transformed cells, thus potentially providing a cancer specific target. A mitochondria-targeted version of the GST substrate 1-chloro-2,4-dinitrobenzene (CDNB), MitoCDNB, has been used to manipulate the mitochondrial GSH pool. To finesse this approach to target particular GST isoforms in the context of cancer, here we have determined the kcat/Km for the human isoforms of GSTK1-1, GSTA1-1 and GSTA4-4 with respect to GSH and CDNB. We show how the rate of the GST-catalysed reaction between GSH and CDNB analogues can be modified by both the electron withdrawing substituents, and by the position of the mitochondria-targeting triphenylphosphonium on the chlorobenzene ring to tune the activity of mitochondria-targeted substrates. These findings can now be exploited to selectively disrupt the mitochondrial GSH pools of cancer cells expressing particular GST isoforms.
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Affiliation(s)
- Patrick A Cardwell
- School of Chemistry, Joseph Black Building, University Avenue, University of Glasgow, Glasgow G12 8QQ, UK.
| | - Carlo Del Moro
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Adrian J Lapthorn
- School of Chemistry, Joseph Black Building, University Avenue, University of Glasgow, Glasgow G12 8QQ, UK
| | - Richard C Hartley
- School of Chemistry, Joseph Black Building, University Avenue, University of Glasgow, Glasgow G12 8QQ, UK.
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2
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Bogetti X, Bogetti A, Casto J, Rule G, Chong L, Saxena S. Direct observation of negative cooperativity in a detoxification enzyme at the atomic level by Electron Paramagnetic Resonance spectroscopy and simulation. Protein Sci 2023; 32:e4770. [PMID: 37632831 PMCID: PMC10503414 DOI: 10.1002/pro.4770] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 07/14/2023] [Accepted: 08/23/2023] [Indexed: 08/28/2023]
Abstract
The catalytic activity of human glutathione S-transferase A1-1 (hGSTA1-1), a homodimeric detoxification enzyme, is dependent on the conformational dynamics of a key C-terminal helix α9 in each monomer. However, the structural details of how the two monomers interact upon binding of substrates is not well understood and the structure of the ligand-free state of the hGSTA1-1 homodimer has not been resolved. Here, we used a combination of electron paramagnetic resonance (EPR) distance measurements and weighted ensemble (WE) simulations to characterize the conformational ensemble of the ligand-free state at the atomic level. EPR measurements reveal a broad distance distribution between a pair of Cu(II) labels in the ligand-free state that gradually shifts and narrows as a function of increasing ligand concentration. These shifts suggest changes in the relative positioning of the two α9 helices upon ligand binding. WE simulations generated unbiased pathways for the seconds-timescale transition between alternate states of the enzyme, leading to the generation of atomically detailed structures of the ligand-free state. Notably, the simulations provide direct observations of negative cooperativity between the monomers of hGSTA1-1, which involve the mutually exclusive docking of α9 in each monomer as a lid over the active site. We identify key interactions between residues that lead to this negative cooperativity. Negative cooperativity may be essential for interaction of hGSTA1-1 with a wide variety of toxic substrates and their subsequent neutralization. More broadly, this work demonstrates the power of integrating EPR distances with WE rare-events sampling strategy to gain mechanistic information on protein function at the atomic level.
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Affiliation(s)
- Xiaowei Bogetti
- Department of ChemistryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Anthony Bogetti
- Department of ChemistryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Joshua Casto
- Department of ChemistryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Gordon Rule
- Department of Biological SciencesCarnegie Mellon UniversityPittsburghPennsylvaniaUSA
| | - Lillian Chong
- Department of ChemistryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Sunil Saxena
- Department of ChemistryUniversity of PittsburghPittsburghPennsylvaniaUSA
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3
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Scian M, Paço L, Murphree TA, Shireman LM, Atkins WM. Reversibility and Low Commitment to Forward Catalysis in the Conjugation of Lipid Alkenals by Glutathione Transferase A4-4. Biomolecules 2023; 13:biom13020329. [PMID: 36830698 PMCID: PMC9953347 DOI: 10.3390/biom13020329] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/31/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
High concentrations of electrophilic lipid alkenals formed during oxidative stress are implicated in cytotoxicity and disease. However, low concentrations of alkenals are required to induce antioxidative stress responses. An established clearance pathway for lipid alkenals includes conjugation to glutathione (GSH) via Michael addition, which is catalyzed mainly by glutathione transferase isoform A4 (GSTA4-4). Based on the ability of GSTs to catalyze hydrolysis or retro-Michael addition of GSH conjugates, and the antioxidant function of low concentrations of lipid alkenals, we hypothesize that GSTA4-4 contributes a homeostatic role in lipid metabolism. Enzymatic kinetic parameters for retro-Michael addition with trans-2-Nonenal (NE) reveal the chemical competence of GSTA4-4 in this putative role. The forward GSTA4-4-catalyzed Michael addition occurs with the rapid exchange of the C2 proton of NE in D2O as observed by NMR. The isotope exchange was completely dependent on the presence of GSH. The overall commitment to catalysis, or the ratio of first order kcat,f for 'forward' Michael addition to the first order kcat,ex for H/D exchange is remarkably low, approximately 3:1. This behavior is consistent with the possibility that GSTA4-4 is a regulatory enzyme that contributes to steady-state levels of lipid alkenals, rather than a strict 'one way' detoxication enzyme.
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4
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Gupta MN, Uversky VN. Pre-Molten, Wet, and Dry Molten Globules en Route to the Functional State of Proteins. Int J Mol Sci 2023; 24:ijms24032424. [PMID: 36768742 PMCID: PMC9916686 DOI: 10.3390/ijms24032424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/23/2023] [Accepted: 01/23/2023] [Indexed: 01/28/2023] Open
Abstract
Transitions between the unfolded and native states of the ordered globular proteins are accompanied by the accumulation of several intermediates, such as pre-molten globules, wet molten globules, and dry molten globules. Structurally equivalent conformations can serve as native functional states of intrinsically disordered proteins. This overview captures the characteristics and importance of these molten globules in both structured and intrinsically disordered proteins. It also discusses examples of engineered molten globules. The formation of these intermediates under conditions of macromolecular crowding and their interactions with nanomaterials are also reviewed.
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Affiliation(s)
- Munishwar Nath Gupta
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India
| | - Vladimir N. Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer’s Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
- Correspondence: ; Tel.: +1-813-494-5816
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5
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Shukla S, Agarwal P, Kumar A. Disordered regions tune order in chromatin organization and function. Biophys Chem 2022; 281:106716. [PMID: 34844028 DOI: 10.1016/j.bpc.2021.106716] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/10/2021] [Accepted: 11/10/2021] [Indexed: 12/29/2022]
Abstract
Intrinsically disordered proteins or hybrid proteins with ordered domains and disordered regions (both collectively designated as IDP(R)s) defy the well-established structure-function paradigm due to their ability to perform multiple biological functions even in the absence of a well-defined 3D structure. IDP(R)s have a unique ability to exist as a functional heterogeneous ensemble, where they adopt multiple thermodynamically stable conformations with low energy barriers between states. The resultant structural plasticity or conformational adaptability provides them with a high functional diversity and ease of regulation. Hence, IDP(R)s are highly efficient biological machinery to mediate intricate cellular functions such as signaling, gene expression, and assembly of complex structures. One such structure is the nucleoprotein complex known as Chromatin. Interestingly, the proteins involved in shaping up the structure and function of chromatin are abundant in disordered regions, which serve more than just as mere flexible linkers. The disordered regions are involved in crucial processes such as gene expression regulation, chromatin architecture maintenance, and liquid-liquid phase separation initiation. This review is an attempt to explore the advantages and the functional and regulatory roles of intrinsic disorder in several Chromatin Associated Proteins from a mechanistic standpoint.
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Affiliation(s)
- Shivangi Shukla
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Prakhar Agarwal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Ashutosh Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India.
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7
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Abstract
Drug metabolizing enzymes catalyze the biotransformation of many of drugs and chemicals. The drug metabolizing enzymes are distributed among several evolutionary families and catalyze a range of detoxication reactions, including oxidation/reduction, conjugative, and hydrolytic reactions that serve to detoxify potentially toxic compounds. This detoxication function requires that drug metabolizing enzymes exhibit substrate promiscuity. In addition to their catalytic functions, many drug metabolizing enzymes possess functions unrelated to or in addition to catalysis. Such proteins are termed 'moonlighting proteins' and are defined as proteins with multiple biochemical or biophysical functions that reside in a single protein. This review discusses the diverse moonlighting functions of drug metabolizing enzymes and the roles they play in physiological functions relating to reproduction, vision, cell signaling, cancer, and transport. Further research will likely reveal new examples of moonlighting functions of drug metabolizing enzymes.
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Affiliation(s)
- Philip G Board
- John Curtin School of Medical Research, ANU College of Health and Medicine, The Australian National University, Canberra, ACT, Australia
| | - M W Anders
- Department of Pharmacology and Physiology, University of Rochester Medical Center, New York, NY, USA
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8
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Cappiello M, Balestri F, Moschini R, Mura U, Del-Corso A. Intra-site differential inhibition of multi-specific enzymes. J Enzyme Inhib Med Chem 2020; 35:840-846. [PMID: 32208768 PMCID: PMC7144184 DOI: 10.1080/14756366.2020.1743988] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The ability to catalyse a reaction acting on different substrates, known as “broad-specificity” or “multi-specificity”, and to catalyse different reactions at the same active site (“promiscuity”) are common features among the enzymes. These properties appear to go against the concept of extreme specificity of the catalytic action of enzymes and have been re-evaluated in terms of evolution and metabolic adaptation. This paper examines the potential usefulness of a differential inhibitory action in the study of the susceptibility to inhibition of multi-specific or promiscuous enzymes acting on different substrates. Aldose reductase is a multi-specific enzyme that catalyses the reduction of both aldoses and hydrophobic cytotoxic aldehydes and is used here as a concrete case to deal with the differential inhibition approach.
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Affiliation(s)
- Mario Cappiello
- Department of Biology, Biochemistry Unit, University of Pisa, Pisa, Italy.,Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy
| | - Francesco Balestri
- Department of Biology, Biochemistry Unit, University of Pisa, Pisa, Italy.,Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy
| | - Roberta Moschini
- Department of Biology, Biochemistry Unit, University of Pisa, Pisa, Italy.,Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy
| | - Umberto Mura
- Department of Biology, Biochemistry Unit, University of Pisa, Pisa, Italy
| | - Antonella Del-Corso
- Department of Biology, Biochemistry Unit, University of Pisa, Pisa, Italy.,Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy
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9
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Singewald K, Bogetti X, Sinha K, Rule GS, Saxena S. Double Histidine Based EPR Measurements at Physiological Temperatures Permit Site‐Specific Elucidation of Hidden Dynamics in Enzymes. Angew Chem Int Ed Engl 2020; 59:23040-23044. [DOI: 10.1002/anie.202009982] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/31/2020] [Indexed: 11/06/2022]
Affiliation(s)
- Kevin Singewald
- Department of Chemistry University of Pittsburgh Pittsburgh PA 15260 USA
| | - Xiaowei Bogetti
- Department of Chemistry University of Pittsburgh Pittsburgh PA 15260 USA
| | - Kaustubh Sinha
- Department of Biological Sciences Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Gordon S Rule
- Department of Biological Sciences Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Sunil Saxena
- Department of Chemistry University of Pittsburgh Pittsburgh PA 15260 USA
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10
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Singewald K, Bogetti X, Sinha K, Rule GS, Saxena S. Double Histidine Based EPR Measurements at Physiological Temperatures Permit Site‐Specific Elucidation of Hidden Dynamics in Enzymes. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009982] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Kevin Singewald
- Department of Chemistry University of Pittsburgh Pittsburgh PA 15260 USA
| | - Xiaowei Bogetti
- Department of Chemistry University of Pittsburgh Pittsburgh PA 15260 USA
| | - Kaustubh Sinha
- Department of Biological Sciences Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Gordon S Rule
- Department of Biological Sciences Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Sunil Saxena
- Department of Chemistry University of Pittsburgh Pittsburgh PA 15260 USA
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11
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Atkins WM. Mechanisms of promiscuity among drug metabolizing enzymes and drug transporters. FEBS J 2020; 287:1306-1322. [PMID: 31663687 PMCID: PMC7138722 DOI: 10.1111/febs.15116] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/04/2019] [Accepted: 10/29/2019] [Indexed: 12/11/2022]
Abstract
Detoxication, or 'drug-metabolizing', enzymes and drug transporters exhibit remarkable substrate promiscuity and catalytic promiscuity. In contrast to substrate-specific enzymes that participate in defined metabolic pathways, individual detoxication enzymes must cope with substrates of vast structural diversity, including previously unencountered environmental toxins. Presumably, evolution selects for a balance of 'adequate' kcat /KM values for a wide range of substrates, rather than optimizing kcat /KM for any individual substrate. However, the structural, energetic, and metabolic properties that achieve this balance, and hence optimize detoxication, are not well understood. Two features of detoxication enzymes that are frequently cited as contributions to promiscuity include the exploitation of highly reactive versatile cofactors, or cosubstrates, and a high degree of flexibility within the protein structure. This review examines these intuitive mechanisms in detail and clarifies the contributions of the classic ligand binding models 'induced fit' (IF) and 'conformational selection' (CS) to substrate promiscuity. The available literature data for drug metabolizing enzymes and transporters suggest that IF is exploited by these promiscuous detoxication enzymes, as it is with substrate-specific enzymes, but the detoxication enzymes uniquely exploit 'IFs' to retain a wide range of substrates at their active sites. In contrast, whereas CS provides no catalytic advantage to substrate-specific enzymes, promiscuous enzymes may uniquely exploit it to recruit a wide range of substrates. The combination of CS and IF, for recruitment and retention of substrates, can potentially optimize the promiscuity of drug metabolizing enzymes and drug transporters.
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Affiliation(s)
- William M. Atkins
- Department of Medicinal ChemistryUniversity of WashingtonSeattleWAUSA
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12
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Balestri F, Barracco V, Renzone G, Tuccinardi T, Pomelli CS, Cappiello M, Lessi M, Rotondo R, Bellina F, Scaloni A, Mura U, Del Corso A, Moschini R. Stereoselectivity of Aldose Reductase in the Reduction of Glutathionyl-Hydroxynonanal Adduct. Antioxidants (Basel) 2019; 8:antiox8100502. [PMID: 31652566 PMCID: PMC6827081 DOI: 10.3390/antiox8100502] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 10/18/2019] [Accepted: 10/21/2019] [Indexed: 12/11/2022] Open
Abstract
The formation of the adduct between the lipid peroxidation product 4-hydroxy-2-nonenal (HNE) and glutathione, which leads to the generation of 3-glutathionyl-4-hydroxynonane (GSHNE), is one of the main routes of HNE detoxification. The aldo-keto reductase AKR1B1 is involved in the reduction of the aldehydic group of both HNE and GSHNE. In the present study, the effect of chirality on the recognition by aldose reductase of HNE and GSHNE was evaluated. AKR1B1 discriminates very modestly between the two possible enantiomers of HNE as substrates. Conversely, a combined kinetic analysis of the glutathionyl adducts obtained starting from either 4R- or 4S-HNE and mass spectrometry analysis of GSHNE products obtained from racemic HNE revealed that AKR1B1 possesses a marked preference toward the 3S,4R-GSHNE diastereoisomer. Density functional theory and molecular modeling studies revealed that this diastereoisomer, besides having a higher tendency to be in an open aldehydic form (the one recognized by AKR1B1) in solution than other GSHNE diastereoisomers, is further stabilized in its open form by a specific interaction with the enzyme active site. The relevance of this stereospecificity to the final metabolic fate of GSHNE is discussed.
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Affiliation(s)
- Francesco Balestri
- Biochemistry Unit, Department of Biology, University of Pisa, via S. Zeno 51, 56127 Pisa, Italy.
- Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, 56124 Pisa, Italy.
| | - Vito Barracco
- Biochemistry Unit, Department of Biology, University of Pisa, via S. Zeno 51, 56127 Pisa, Italy.
| | - Giovanni Renzone
- Proteomics & Mass Spectrometry Laboratory, ISPAAM-CNR, Via Argine 1085, 80147 Napoli, Italy.
| | - Tiziano Tuccinardi
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | | | - Mario Cappiello
- Biochemistry Unit, Department of Biology, University of Pisa, via S. Zeno 51, 56127 Pisa, Italy.
- Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, 56124 Pisa, Italy.
| | - Marco Lessi
- Department of Chemistry and Industrial Chemistry, University of Pisa, via G. Moruzzi, 13, 56124 Pisa, Italy.
| | - Rossella Rotondo
- Biochemistry Unit, Department of Biology, University of Pisa, via S. Zeno 51, 56127 Pisa, Italy.
| | - Fabio Bellina
- Department of Chemistry and Industrial Chemistry, University of Pisa, via G. Moruzzi, 13, 56124 Pisa, Italy.
| | - Andrea Scaloni
- Proteomics & Mass Spectrometry Laboratory, ISPAAM-CNR, Via Argine 1085, 80147 Napoli, Italy.
| | - Umberto Mura
- Biochemistry Unit, Department of Biology, University of Pisa, via S. Zeno 51, 56127 Pisa, Italy.
| | - Antonella Del Corso
- Biochemistry Unit, Department of Biology, University of Pisa, via S. Zeno 51, 56127 Pisa, Italy.
- Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, 56124 Pisa, Italy.
| | - Roberta Moschini
- Biochemistry Unit, Department of Biology, University of Pisa, via S. Zeno 51, 56127 Pisa, Italy.
- Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, 56124 Pisa, Italy.
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13
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Interaction of glutathione S-transferase polymorphisms and tobacco smoking during pregnancy in susceptibility to autism spectrum disorders. Sci Rep 2019; 9:3206. [PMID: 30824761 PMCID: PMC6397281 DOI: 10.1038/s41598-019-39885-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 01/30/2019] [Indexed: 12/20/2022] Open
Abstract
Autism spectrum disorders (ASD) are a group of complex psychiatric disorders, with a proposed gene-environment interaction in their etiology. One mechanism that could explain both the genetic and environmental component is oxidative stress. The aim of our study was to investigate the potential role of common polymorphisms in genes for glutathione transferase A1, M1, T1 and P1 in susceptibility to ASD. We also aimed to explore the possible oxidative stress - specific gene-environment interaction, regarding GST polymorphisms, maternal smoking tobacco during pregnancy (TSDP) and the risk of ASD. This case-control study included 113 children with ASD and 114 age and sex-matched controls. The diagnosis was made based on ICD-10 criteria and verified by Autism Diagnostic Interview – Revised (ADI-R). We investigated GSTA1, GSTM1, GSTP1 and GSTT1 genotypes and explored their individual and combined effects in individuals with ASD. Individual effect of GST genotypes was shown for GSTM1 active genotype decreasing the risk of ASD (OR = 0.554, 95%CI: 0.313–0.983, p = 0.044), and for GSTA1 CC genotype, increasing susceptibility to ASD (OR = 4.132, 95%CI: 1.219–14.012, p = 0.023); the significance was lost when genotype-genotype interactions were added into the logistic regression model. The combination of GSTM1 active and GSTT1 active genotype decreased the risk of ASD (OR = 0.126, 95%CI: 0.029–0.547, p = 0.006), as well as combination of GSTT1 active and GSTP1 llelle (OR = 0.170, 95%CI: 0.029–0.992, p = 0.049). Increased risk of ASD was observed if combination of GSTM1 active and GSTP1 llelle was present (OR = 11.088, 95%CI: 1.745–70.456, p = 0.011). The effect of TSDP was not significant for the risk of ASD, neither individually, nor in interaction with specific GST genotypes. Specific combination of GST genotypes might be associated with susceptibility to ASD, while it appears that maternal smoking during pregnancy does not increase the risk of ASD.
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14
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Lawless MJ, Pettersson JR, Rule GS, Lanni F, Saxena S. ESR Resolves the C Terminus Structure of the Ligand-free Human Glutathione S-Transferase A1-1. Biophys J 2019; 114:592-601. [PMID: 29414705 DOI: 10.1016/j.bpj.2017.12.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 12/11/2017] [Accepted: 12/18/2017] [Indexed: 01/05/2023] Open
Abstract
Nitroxide- and Cu2+-based electron spin resonance (ESR) are combined to provide insight into the conformational states of the functionally important α-helix of the human glutathione S-transferase A1. Distance measurements on various spin-labeled dimeric human glutathione S-transferase A1-1 all result in bimodal distance distributions, indicating that the C-terminus exists in two distinct conformations in solution, one of which closely matches that found in the crystal structure of the ligand-bound enzyme. These measurements permit the generation of a model of the unliganded conformation. Room temperature ESR indicates that the second conformation has high mobility, potentially enabling the enzyme's high degree of substrate promiscuity. This model is then validated using computational modeling and further Cu2+-based ESR distance measurements. Cu2+-based ESR also provides evidence that the secondary structure of the second conformation is of helical nature. Addition of S-hexyl glutathione results in a shift in relative populations, favoring the state that is similar to the previously known structure of the ligand-bound enzyme.
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Affiliation(s)
- Matthew J Lawless
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - John R Pettersson
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Gordon S Rule
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Frederick Lanni
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania.
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15
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Allosteric Modulation of Binding Specificity by Alternative Packing of Protein Cores. J Mol Biol 2018; 431:336-350. [PMID: 30471255 DOI: 10.1016/j.jmb.2018.11.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 11/04/2018] [Accepted: 11/14/2018] [Indexed: 11/21/2022]
Abstract
Hydrophobic cores are often viewed as tightly packed and rigid, but they do show some plasticity and could thus be attractive targets for protein design. Here we explored the role of different functional pressures on the core packing and ligand recognition of the SH3 domain from human Fyn tyrosine kinase. We randomized the hydrophobic core and used phage display to select variants that bound to each of three distinct ligands. The three evolved groups showed remarkable differences in core composition, illustrating the effect of different selective pressures on the core. Changes in the core did not significantly alter protein stability, but were linked closely to changes in binding affinity and specificity. Structural analysis and molecular dynamics simulations revealed the structural basis for altered specificity. The evolved domains had significantly reduced core volumes, which in turn induced increased backbone flexibility. These motions were propagated from the core to the binding surface and induced significant conformational changes. These results show that alternative core packing and consequent allosteric modulation of binding interfaces could be used to engineer proteins with novel functions.
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16
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Pettersson JR, Lanni F, Rule GS. Dual Lifetimes for Complexes between Glutathione-S-transferase (hGSTA1-1) and Product-like Ligands Detected by Single-Molecule Fluorescence Imaging. Biochemistry 2017; 56:4073-4083. [PMID: 28677395 DOI: 10.1021/acs.biochem.7b00030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Single-molecule fluorescence techniques were used to characterize the binding of products and inhibitors to human glutathione S-transferase A1-1 (hGSTA1-1). The identification of at least two different bound states for the wild-type enzyme suggests that there are at least two conformations of the protein, consistent with the model that ligand binding promotes closure of the carboxy-terminal helix over the active site. Ligand induced changes in ensemble fluorescence energy transfer support this proposed structural change. The more predominant state in the ensemble of single molecules shows a significantly faster off-rate, suggesting that the carboxy-terminal helix is delocalized in this state, permitting faster exit of the bound ligand. A point mutation (I219A), which is known to interfere with the association of the carboxy-terminal helix with the enzyme, shows increased rates of interconversion between the open and closed state. Kinematic traces of fluorescence from single molecules show that a single molecule readily samples a number of different conformations, each with a characteristic off-rate.
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Affiliation(s)
- John R Pettersson
- Department of Biological Sciences, Carnegie Mellon University , Pittsburgh, Pennsylvania, United States
| | - Frederick Lanni
- Department of Biological Sciences, Carnegie Mellon University , Pittsburgh, Pennsylvania, United States
| | - Gordon S Rule
- Department of Biological Sciences, Carnegie Mellon University , Pittsburgh, Pennsylvania, United States
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17
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Mohana K, Achary A. Human cytosolic glutathione-S-transferases: quantitative analysis of expression, comparative analysis of structures and inhibition strategies of isozymes involved in drug resistance. Drug Metab Rev 2017; 49:318-337. [DOI: 10.1080/03602532.2017.1343343] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Krishnamoorthy Mohana
- Department of Biotechnology, Centre for Research, Kamaraj College of Engineering and Technology, Virudhunagar, India
| | - Anant Achary
- Department of Biotechnology, Centre for Research, Kamaraj College of Engineering and Technology, Virudhunagar, India
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18
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Levin M, Udi Y, Solomonov I, Sagi I. Next generation matrix metalloproteinase inhibitors - Novel strategies bring new prospects. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017. [PMID: 28636874 DOI: 10.1016/j.bbamcr.2017.06.009] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Enzymatic proteolysis of cell surface proteins and extracellular matrix (ECM) is critical for tissue homeostasis and cell signaling. These proteolytic activities are mediated predominantly by a family of proteases termed matrix metalloproteinases (MMPs). The growing evidence in recent years that ECM and non-ECM bioactive molecules (e.g., growth factors, cytokines, chemokines, on top of matrikines and matricryptins) have versatile functions redefines our view on the roles matrix remodeling enzymes play in many physiological and pathological processes, and underscores the notion that ECM proteolytic reaction mechanisms represent master switches in the regulation of critical biological processes and govern cell behavior. Accordingly, MMPs are not only responsible for direct degradation of ECM molecules but are also key modulators of cardinal bioactive factors. Many attempts were made to manipulate ECM degradation by targeting MMPs using small peptidic and organic inhibitors. However, due to the high structural homology shared by these enzymes, the majority of the developed compounds are broad-spectrum inhibitors affecting the proteolytic activity of various MMPs and other zinc-related proteases. These inhibitors, in many cases, failed as therapeutic agents, mainly due to the bilateral role of MMPs in pathological conditions such as cancer, in which MMPs have both pro- and anti-tumorigenic effects. Despite the important role of MMPs in many human diseases, none of the broad-range synthetic MMP inhibitors that were designed have successfully passed clinical trials. It appears that, designing highly selective MMP inhibitors that are also effective in vivo, is not trivial. The challenges related to designing selective and effective metalloprotease inhibitors, are associated in part with the aforesaid high structural homology and the dynamic nature of their protein scaffolds. Great progress was achieved in the last decade in understanding the biochemistry and biology of MMPs activity. This knowledge, combined with lessons from the past has drawn new "boundaries" for the development of the next-generation MMP inhibitors. These novel agents are currently designed to be highly specific, capable to discriminate between the homologous MMPs and ideally administered as a short-term topical treatment. In this review we discuss the latest progress in the fields of MMP inhibitors in terms of structure, function and their specific activity. The development of novel highly specific inhibitors targeting MMPs paves the path to study complex biological processes associated with ECM proteolysis in health and disease. This article is part of a Special Issue entitled: Matrix Metalloproteinases edited by Rafael Fridman.
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Affiliation(s)
- Maxim Levin
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yael Udi
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY 10065, USA
| | - Inna Solomonov
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Irit Sagi
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel.
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19
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Valenzuela-Chavira I, Contreras-Vergara CA, Arvizu-Flores AA, Serrano-Posada H, Lopez-Zavala AA, García-Orozco KD, Hernandez-Paredes J, Rudiño-Piñera E, Stojanoff V, Sotelo-Mundo RR, Islas-Osuna MA. Insights into ligand binding to a glutathione S-transferase from mango: Structure, thermodynamics and kinetics. Biochimie 2017; 135:35-45. [PMID: 28104507 PMCID: PMC5346462 DOI: 10.1016/j.biochi.2017.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/08/2016] [Accepted: 01/01/2017] [Indexed: 02/08/2023]
Abstract
We studied a mango glutathione S-transferase (GST) (Mangifera indica) bound to glutathione (GSH) and S-hexyl glutathione (GSX). This GST Tau class (MiGSTU) had a molecular mass of 25.5 kDa. MiGSTU Michaelis-Menten kinetic constants were determined for their substrates obtaining a Km, Vmax and kcat for CDNB of 0.792 mM, 80.58 mM min-1 and 68.49 s-1 respectively and 0.693 mM, 105.32 mM min-1 and 89.57 s-1, for reduced GSH respectively. MiGSTU had a micromolar affinity towards GSH (5.2 μM) or GSX (7.8 μM). The crystal structure of the MiGSTU in apo or bound to GSH or GSX generated a model that explains the thermodynamic signatures of binding and showed the importance of enthalpic-entropic compensation in ligand binding to Tau-class GST enzymes.
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Affiliation(s)
- Ignacio Valenzuela-Chavira
- Laboratorio de Estructura Biomolecular, Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Hermosillo, Sonora 83304, Mexico; Laboratorio de Genética Molecular de Plantas, Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Hermosillo, Sonora 83304, Mexico
| | - Carmen A Contreras-Vergara
- Laboratorio de Genética Molecular de Plantas, Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Hermosillo, Sonora 83304, Mexico.
| | - Aldo A Arvizu-Flores
- Departamento de Ciencias Químico Biológicas, Universidad de Sonora, Hermosillo, Sonora 83000, Mexico
| | - Hugo Serrano-Posada
- CONACyT, Laboratorio de Bioingeniería, Universidad de Colima, Coquimatlán, Colima 28629, Mexico
| | - Alonso A Lopez-Zavala
- Departamento de Ciencias Químico Biológicas, Universidad de Sonora, Hermosillo, Sonora 83000, Mexico
| | - Karina D García-Orozco
- Laboratorio de Estructura Biomolecular, Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Hermosillo, Sonora 83304, Mexico
| | | | - Enrique Rudiño-Piñera
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología (IBT), Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos 62210, Mexico
| | - Vivian Stojanoff
- Brookhaven National Laboratory, Photon Science Directorate, Upton, NY 11973, USA
| | - Rogerio R Sotelo-Mundo
- Laboratorio de Estructura Biomolecular, Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Hermosillo, Sonora 83304, Mexico.
| | - Maria A Islas-Osuna
- Laboratorio de Genética Molecular de Plantas, Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Hermosillo, Sonora 83304, Mexico
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20
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Devamani T, Rauwerdink AM, Lun-zer M, Jones BJ, Mooney JL, Tan MAO, Zhang ZJ, Xu JH, Dean AM, Kazlauskas RJ. Catalytic Promiscuity of Ancestral Esterases and Hydroxynitrile Lyases. J Am Chem Soc 2016; 138:1046-56. [PMID: 26736133 PMCID: PMC5466365 DOI: 10.1021/jacs.5b12209] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Catalytic promiscuity is a useful, but accidental, enzyme property, so finding catalytically promiscuous enzymes in nature is inefficient. Some ancestral enzymes were branch points in the evolution of new enzymes and are hypothesized to have been promiscuous. To test the hypothesis that ancestral enzymes were more promiscuous than their modern descendants, we reconstructed ancestral enzymes at four branch points in the divergence hydroxynitrile lyases (HNL's) from esterases ∼ 100 million years ago. Both enzyme types are α/β-hydrolase-fold enzymes and have the same catalytic triad, but differ in reaction type and mechanism. Esterases catalyze hydrolysis via an acyl enzyme intermediate, while lyases catalyze an elimination without an intermediate. Screening ancestral enzymes and their modern descendants with six esterase substrates and six lyase substrates found higher catalytic promiscuity among the ancestral enzymes (P < 0.01). Ancestral esterases were more likely to catalyze a lyase reaction than modern esterases, and the ancestral HNL was more likely to catalyze ester hydrolysis than modern HNL's. One ancestral enzyme (HNL1) along the path from esterase to hydroxynitrile lyases was especially promiscuous and catalyzed both hydrolysis and lyase reactions with many substrates. A broader screen tested mechanistically related reactions that were not selected for by evolution: decarboxylation, Michael addition, γ-lactam hydrolysis and 1,5-diketone hydrolysis. The ancestral enzymes were more promiscuous than their modern descendants (P = 0.04). Thus, these reconstructed ancestral enzymes are catalytically promiscuous, but HNL1 is especially so.
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Affiliation(s)
- Titu Devamani
- University of Minnesota, Department of Biochemistry, Molecular Biology & Biophysics and The Biotechnology Institute, 1479 Gortner Avenue, Saint Paul, MN 55108 USA
| | - Alissa M. Rauwerdink
- University of Minnesota, Department of Biochemistry, Molecular Biology & Biophysics and The Biotechnology Institute, 1479 Gortner Avenue, Saint Paul, MN 55108 USA
| | - Mark Lun-zer
- University of Minnesota, Department of Ecology, Evolution & Behavior and The Biotechnology Institute, 1479 Gortner Avenue, Saint Paul, MN 55108 USA
| | - Bryan J. Jones
- University of Minnesota, Department of Biochemistry, Molecular Biology & Biophysics and The Biotechnology Institute, 1479 Gortner Avenue, Saint Paul, MN 55108 USA
| | - Joanna L. Mooney
- University of Minnesota, Department of Biochemistry, Molecular Biology & Biophysics and The Biotechnology Institute, 1479 Gortner Avenue, Saint Paul, MN 55108 USA
| | | | - Zhi-Jun Zhang
- East China University of Science and Technology, School of Biotechnology, Meilong Road 130, Shanghai 200237 P. R. China
| | - Jian-He Xu
- East China University of Science and Technology, School of Biotechnology, Meilong Road 130, Shanghai 200237 P. R. China
| | - Antony M. Dean
- University of Minnesota, Department of Ecology, Evolution & Behavior and The Biotechnology Institute, 1479 Gortner Avenue, Saint Paul, MN 55108 USA
- Sun Yat-sen University, Institute of Ecology and Evolution, No.135, Xinggang West Road, Guangzhou, 510275 P. R. China
| | - Romas J. Kazlauskas
- University of Minnesota, Department of Biochemistry, Molecular Biology & Biophysics and The Biotechnology Institute, 1479 Gortner Avenue, Saint Paul, MN 55108 USA
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21
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Woods KN, Pfeffer J. Using THz Spectroscopy, Evolutionary Network Analysis Methods, and MD Simulation to Map the Evolution of Allosteric Communication Pathways in c-Type Lysozymes. Mol Biol Evol 2016; 33:40-61. [PMID: 26337549 PMCID: PMC4693973 DOI: 10.1093/molbev/msv178] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
It is now widely accepted that protein function is intimately tied with the navigation of energy landscapes. In this framework, a protein sequence is not described by a distinct structure but rather by an ensemble of conformations. And it is through this ensemble that evolution is able to modify a protein's function by altering its landscape. Hence, the evolution of protein functions involves selective pressures that adjust the sampling of the conformational states. In this work, we focus on elucidating the evolutionary pathway that shaped the function of individual proteins that make-up the mammalian c-type lysozyme subfamily. Using both experimental and computational methods, we map out specific intermolecular interactions that direct the sampling of conformational states and accordingly, also underlie shifts in the landscape that are directly connected with the formation of novel protein functions. By contrasting three representative proteins in the family we identify molecular mechanisms that are associated with the selectivity of enhanced antimicrobial properties and consequently, divergent protein function. Namely, we link the extent of localized fluctuations involving the loop separating helices A and B with shifts in the equilibrium of the ensemble of conformational states that mediate interdomain coupling and concurrently moderate substrate binding affinity. This work reveals unique insights into the molecular level mechanisms that promote the progression of interactions that connect the immune response to infection with the nutritional properties of lactation, while also providing a deeper understanding about how evolving energy landscapes may define present-day protein function.
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22
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Atkins WM. Biological messiness vs. biological genius: Mechanistic aspects and roles of protein promiscuity. J Steroid Biochem Mol Biol 2015; 151:3-11. [PMID: 25218442 PMCID: PMC4920067 DOI: 10.1016/j.jsbmb.2014.09.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 08/28/2014] [Accepted: 09/09/2014] [Indexed: 02/06/2023]
Abstract
In contrast to the traditional biological paradigms focused on 'specificity', recent research and theoretical efforts have focused on functional 'promiscuity' exhibited by proteins and enzymes in many biological settings, including enzymatic detoxication, steroid biochemistry, signal transduction and immune responses. In addition, divergent evolutionary processes are apparently facilitated by random mutations that yield promiscuous enzyme intermediates. The intermediates, in turn, provide opportunities for further evolution to optimize new functions from existing protein scaffolds. In some cases, promiscuity may simply represent the inherent plasticity of proteins resulting from their polymeric nature with distributed conformational ensembles. Enzymes or proteins that bind or metabolize noncognate substrates create 'messiness' or noise in the systems they contribute to. With our increasing awareness of the frequency of these promiscuous behaviors it becomes interesting and important to understand the molecular bases for promiscuous behavior and to distinguish between evolutionarily selected promiscuity and evolutionarily tolerated messiness. This review provides an overview of current understanding of these aspects of protein biochemistry and enzymology.
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Affiliation(s)
- William M Atkins
- Department of Medicinal Chemistry, Box 357610, University of Washington, Seattle, WA 98195-7610, USA.
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23
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Zhang W, Dourado DF, Mannervik B. Evolution of the active site of human glutathione transferase A2-2 for enhanced activity with dietary isothiocyanates. Biochim Biophys Acta Gen Subj 2015; 1850:742-9. [DOI: 10.1016/j.bbagen.2014.12.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 12/10/2014] [Accepted: 12/19/2014] [Indexed: 11/29/2022]
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24
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Labrou NE, Papageorgiou AC, Pavli O, Flemetakis E. Plant GSTome: structure and functional role in xenome network and plant stress response. Curr Opin Biotechnol 2015; 32:186-194. [PMID: 25614070 DOI: 10.1016/j.copbio.2014.12.024] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 12/20/2014] [Accepted: 12/30/2014] [Indexed: 10/24/2022]
Abstract
Glutathione transferases (GSTs) represent a major group of detoxification enzymes. All plants possess multiple cytosolic GSTs, each of which displays distinct catalytic as well as non-catalytic binding properties. The progress made in recent years in the fields of genomics, proteomics and protein crystallography of GSTs, coupled with studies on their molecular evolution, diversity and substrate specificity has provided new insights into the function of these enzymes. In plants, GSTs appear to be implicated in an array of different functions, including detoxification of xenobiotics and endobiotics, primary and secondary metabolism, stress tolerance, and cell signalling. This review focuses on plant GSTome and attempts to give an overview of its catalytic and functional role in xenome and plant stress regulatory networks.
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Affiliation(s)
- Nikolaos E Labrou
- Laboratory of Enzyme Technology, Department of Biotechnology, School of Food, Biotechnology and Development, Agricultural University of Athens, 75 Iera Odos Street, GR-11855 Athens, Greece.
| | | | - Ourania Pavli
- University of Thessaly, School of Agricultural Sciences, Department of Agriculture, Crop Production and Rural Environment, Fytokoy Street, 384 46 N. Ionia, Magnisia, Greece
| | - Emmanouil Flemetakis
- Laboratory of Molecular Biology, Department of Biotechnology, School of Food, Biotechnology and Development, Agricultural University of Athens, Athens, Greece
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25
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Hegedüs C, Hegedüs T, Sarkadi B. The Role of ABC Multidrug Transporters in Resistance to Targeted Anticancer Kinase Inhibitors. RESISTANCE TO TARGETED ANTI-CANCER THERAPEUTICS 2015. [DOI: 10.1007/978-3-319-09801-2_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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26
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Pitsawong W, Hoben JP, Miller AF. Understanding the broad substrate repertoire of nitroreductase based on its kinetic mechanism. J Biol Chem 2014; 289:15203-14. [PMID: 24706760 DOI: 10.1074/jbc.m113.547117] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The oxygen-insensitive nitroreductase from Enterobacter cloacae (NR) catalyzes two-electron reduction of nitroaromatics to the corresponding nitroso compounds and, subsequently, to hydroxylamine products. NR has an unusually broad substrate repertoire, which may be related to protein dynamics (flexibility) and/or a simple non-selective kinetic mechanism. To investigate the possible role of mechanism in the broad substrate repertoire of NR, the kinetics of oxidation of NR by para-nitrobenzoic acid (p-NBA) were investigated using stopped-flow techniques at 4 °C. The results revealed a hyperbolic dependence on the p-NBA concentration with a limiting rate of 1.90 ± 0.09 s(-1), indicating one-step binding before the flavin oxidation step. There is no evidence for a distinct binding step in which specificity might be enforced. The reduction of p-NBA is rate-limiting in steady-state turnover (1.7 ± 0.3 s(-1)). The pre-steady-state reduction kinetics of NR by NADH indicate that NADH reduces the enzyme with a rate constant of 700 ± 20 s(-1) and a dissociation constant of 0.51 ± 0.04 mM. Thus, we demonstrate simple transient kinetics in both the reductive and oxidative half-reactions that help to explain the broad substrate repertoire of NR. Finally, we tested the ability of NR to reduce para-hydroxylaminobenzoic acid, demonstrating that the corresponding amine does not accumulate to significant levels even under anaerobic conditions. Thus E. cloacae NR is not a good candidate for enzymatic production of aromatic amines.
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Affiliation(s)
- Warintra Pitsawong
- From the Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055
| | - John P Hoben
- From the Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055
| | - Anne-Frances Miller
- From the Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055
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27
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Hiblot J, Gotthard G, Elias M, Chabriere E. Differential active site loop conformations mediate promiscuous activities in the lactonase SsoPox. PLoS One 2013; 8:e75272. [PMID: 24086491 PMCID: PMC3781021 DOI: 10.1371/journal.pone.0075272] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 08/14/2013] [Indexed: 11/19/2022] Open
Abstract
Enzymes are proficient catalysts that enable fast rates of Michaelis-complex formation, the chemical step and products release. These different steps may require different conformational states of the active site that have distinct binding properties. Moreover, the conformational flexibility of the active site mediates alternative, promiscuous functions. Here we focused on the lactonase SsoPox from Sulfolobus solfataricus. SsoPox is a native lactonase endowed with promiscuous phosphotriesterase activity. We identified a position in the active site loop (W263) that governs its flexibility, and thereby affects the substrate specificity of the enzyme. We isolated two different sets of substitutions at position 263 that induce two distinct conformational sampling of the active loop and characterized the structural and kinetic effects of these substitutions. These sets of mutations selectively and distinctly mediate the improvement of the promiscuous phosphotriesterase and oxo-lactonase activities of SsoPox by increasing active-site loop flexibility. These observations corroborate the idea that conformational diversity governs enzymatic promiscuity and is a key feature of protein evolvability.
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Affiliation(s)
- Julien Hiblot
- URMITE UMR CNRS-IRD 6236, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
| | - Guillaume Gotthard
- URMITE UMR CNRS-IRD 6236, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
| | - Mikael Elias
- Weizmann Institute of Science, Biological Chemistry, Rehovot, Israel
| | - Eric Chabriere
- URMITE UMR CNRS-IRD 6236, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
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28
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Zhu X, Wang B, Kan X, Chen C, Yu C. Evolution of plant Ash1 SET genes: structural divergence and functional differentiation. Genes Genomics 2013. [DOI: 10.1007/s13258-013-0056-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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29
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Employing directed evolution for the functional analysis of multi-specific proteins. Bioorg Med Chem 2013; 21:3511-6. [DOI: 10.1016/j.bmc.2013.04.052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 04/11/2013] [Accepted: 04/18/2013] [Indexed: 01/17/2023]
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30
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Honaker MT, Acchione M, Zhang W, Mannervik B, Atkins WM. Enzymatic detoxication, conformational selection, and the role of molten globule active sites. J Biol Chem 2013; 288:18599-611. [PMID: 23649628 DOI: 10.1074/jbc.m112.445767] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The role of conformational ensembles in enzymatic reactions remains unclear. Discussion concerning "induced fit" versus "conformational selection" has, however, ignored detoxication enzymes, which exhibit catalytic promiscuity. These enzymes dominate drug metabolism and determine drug-drug interactions. The detoxication enzyme glutathione transferase A1-1 (GSTA1-1), exploits a molten globule-like active site to achieve remarkable catalytic promiscuity wherein the substrate-free conformational ensemble is broad with barrierless transitions between states. A quantitative index of catalytic promiscuity is used to compare engineered variants of GSTA1-1 and the catalytic promiscuity correlates strongly with characteristics of the thermodynamic partition function, for the substrate-free enzymes. Access to chemically disparate transition states is encoded by the substrate-free conformational ensemble. Pre-steady state catalytic data confirm an extension of the conformational selection model, wherein different substrates select different starting conformations. The kinetic liability of the conformational breadth is minimized by a smooth landscape. We propose that "local" molten globule behavior optimizes detoxication enzymes.
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Affiliation(s)
- Matthew T Honaker
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195-7610, USA
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31
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Abstract
Though lacking a well-defined three-dimensional structure, intrinsically unstructured proteins are ubiquitous in nature. These molecules play crucial roles in many cellular processes, especially signaling and regulation. Surprisingly, even enzyme catalysis can tolerate substantial disorder. This observation contravenes conventional wisdom but is relevant to an understanding of how protein dynamics modulates enzyme function. This chapter reviews properties and characteristics of disordered proteins, emphasizing examples of enzymes that lack defined structures, and considers implications of structural disorder for catalytic efficiency and evolution.
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32
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Human cytosolic glutathione transferases: structure, function, and drug discovery. Trends Pharmacol Sci 2012; 33:656-68. [DOI: 10.1016/j.tips.2012.09.007] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 09/26/2012] [Accepted: 09/27/2012] [Indexed: 11/19/2022]
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33
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Chronopoulou E, Madesis P, Asimakopoulou B, Platis D, Tsaftaris A, Labrou NE. Catalytic and structural diversity of the fluazifop-inducible glutathione transferases from Phaseolus vulgaris. PLANTA 2012; 235:1253-1269. [PMID: 22203322 DOI: 10.1007/s00425-011-1572-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 12/05/2011] [Indexed: 05/31/2023]
Abstract
Plant glutathione transferases (GSTs) comprise a large family of inducible enzymes that play important roles in stress tolerance and herbicide detoxification. Treatment of Phaseolus vulgaris leaves with the aryloxyphenoxypropionic herbicide fluazifop-p-butyl resulted in induction of GST activities. Three inducible GST isoenzymes were identified and separated by affinity chromatography. Their full-length cDNAs with complete open reading frame were isolated using RACE-RT and information from N-terminal amino acid sequences. Analysis of the cDNA clones showed that the deduced amino acid sequences share high homology with GSTs that belong to phi and tau classes. The three isoenzymes were expressed in E. coli and their substrate specificity was determined towards 20 different substrates. The results showed that the fluazifop-inducible glutathione transferases from P. vulgaris (PvGSTs) catalyze a broad range of reactions and exhibit quite varied substrate specificity. Molecular modeling and structural analysis was used to identify key structural characteristics and to provide insights into the substrate specificity and the catalytic mechanism of these enzymes. These results provide new insights into catalytic and structural diversity of GSTs and the detoxifying mechanism used by P. vulgaris.
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Affiliation(s)
- Evangelia Chronopoulou
- Laboratory of Enzyme Technology, Department of Agricultural Biotechnology, Agricultural University of Athens, 75 Iera Odos Street, 11855 Athens, Greece
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34
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Ben-David M, Elias M, Filippi JJ, Duñach E, Silman I, Sussman JL, Tawfik DS. Catalytic versatility and backups in enzyme active sites: the case of serum paraoxonase 1. J Mol Biol 2012; 418:181-96. [PMID: 22387469 DOI: 10.1016/j.jmb.2012.02.042] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/19/2012] [Accepted: 02/22/2012] [Indexed: 12/15/2022]
Abstract
The origins of enzyme specificity are well established. However, the molecular details underlying the ability of a single active site to promiscuously bind different substrates and catalyze different reactions remain largely unknown. To better understand the molecular basis of enzyme promiscuity, we studied the mammalian serum paraoxonase 1 (PON1) whose native substrates are lipophilic lactones. We describe the crystal structures of PON1 at a catalytically relevant pH and of its complex with a lactone analogue. The various PON1 structures and the analysis of active-site mutants guided the generation of docking models of the various substrates and their reaction intermediates. The models suggest that promiscuity is driven by coincidental overlaps between the reactive intermediate for the native lactonase reaction and the ground and/or intermediate states of the promiscuous reactions. This overlap is also enabled by different active-site conformations: the lactonase activity utilizes one active-site conformation whereas the promiscuous phosphotriesterase activity utilizes another. The hydrolysis of phosphotriesters, and of the aromatic lactone dihydrocoumarin, is also driven by an alternative catalytic mode that uses only a subset of the active-site residues utilized for lactone hydrolysis. Indeed, PON1's active site shows a remarkable level of networking and versatility whereby multiple residues share the same task and individual active-site residues perform multiple tasks (e.g., binding the catalytic calcium and activating the hydrolytic water). Overall, the coexistence of multiple conformations and alternative catalytic modes within the same active site underlines PON1's promiscuity and evolutionary potential.
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Affiliation(s)
- Moshe Ben-David
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
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Kokkinidis M, Glykos N, Fadouloglou V. Protein Flexibility and Enzymatic Catalysis. STRUCTURAL AND MECHANISTIC ENZYMOLOGY - BRINGING TOGETHER EXPERIMENTS AND COMPUTING 2012; 87:181-218. [DOI: 10.1016/b978-0-12-398312-1.00007-x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Honaker MT, Acchione M, Sumida JP, Atkins WM. Ensemble perspective for catalytic promiscuity: calorimetric analysis of the active site conformational landscape of a detoxification enzyme. J Biol Chem 2011; 286:42770-42776. [PMID: 22002059 DOI: 10.1074/jbc.m111.304386] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Enzymological paradigms have shifted recently to acknowledge the biological importance of catalytic promiscuity. However, catalytic promiscuity is a poorly understood property, and no thermodynamic treatment has described the conformational landscape of promiscuous versus substrate-specific enzymes. Here, two structurally similar glutathione transferase (GST, glutathione S-transferase) isoforms with high specificity or high promiscuity are compared. Differential scanning calorimetry (DSC) indicates a reversible low temperature transition for the promiscuous GSTA1-1 that is not observed with substrate-specific GSTA4-4. This transition is assigned to rearrangement of the C terminus at the active site of GSTA1-1 based on the effects of ligands and mutations. Near-UV and far-UV circular dichroism indicate that this transition is due to repacking of tertiary contacts with the remainder of the subunit, rather than "unfolding" of the C terminus per se. Analysis of the DSC data using a modified Landau theory indicates that the local conformational landscape of the active site of GSTA1-1 is smooth, with barrierless transitions between states. The partition function of the C-terminal states is a broad unimodal distribution at all temperatures within this DSC transition. In contrast, the remainder of the GSTA1-1 subunit and the GSTA4-4 protein exhibit folded and unfolded macrostates with a significant energy barrier separating them. Their partition function includes a sharp unimodal distribution of states only at temperatures that yield either folded or unfolded macrostates. At intermediate temperatures the partition function includes a bimodal distribution. The barrierless rearrangement of the GSTA1-1 active site within a local smooth energy landscape suggests a thermodynamic basis for catalytic promiscuity.
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Affiliation(s)
- Matthew T Honaker
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98177-7610
| | - Mauro Acchione
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98177-7610
| | - John P Sumida
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98177-7610
| | - William M Atkins
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98177-7610.
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Parbhoo N, Stoychev SH, Fanucchi S, Achilonu I, Adamson RJ, Fernandes M, Gildenhuys S, Dirr HW. A Conserved Interdomain Interaction Is a Determinant of Folding Cooperativity in the GST Fold. Biochemistry 2011; 50:7067-75. [DOI: 10.1021/bi2006509] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nishal Parbhoo
- Protein Structure−Function
Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050,
South Africa
| | - Stoyan H. Stoychev
- Protein Structure−Function
Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050,
South Africa
| | - Sylvia Fanucchi
- Protein Structure−Function
Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050,
South Africa
| | - Ikechukwu Achilonu
- Protein Structure−Function
Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050,
South Africa
| | - Roslin J. Adamson
- Protein Structure−Function
Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050,
South Africa
| | - Manuel Fernandes
- School of
Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa
| | - Samantha Gildenhuys
- Protein Structure−Function
Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050,
South Africa
| | - Heini W. Dirr
- Protein Structure−Function
Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050,
South Africa
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Atkins WM, Qian H. Stochastic ensembles, conformationally adaptive teamwork, and enzymatic detoxification. Biochemistry 2011; 50:3866-72. [PMID: 21473615 DOI: 10.1021/bi200275r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
It has been appreciated for a long time that enzymes exist as conformational ensembles throughout multiple stages of the reactions they catalyze, but there is renewed interest in the functional implications. The energy landscape that results from conformationlly diverse poteins is a complex surface with an energetic topography in multiple dimensions, even at the transition state(s) leading to product formation, and this represents a new paradigm. At the same time there has been renewed interest in conformational ensembles, a new paradigm concerning enzyme function has emerged, wherein catalytic promiscuity has clear biological advantages in some cases. "Useful", or biologically functional, promiscuity or the related behavior of "multifunctionality" can be found in the immune system, enzymatic detoxification, signal transduction, and the evolution of new function from an existing pool of folded protein scaffolds. Experimental evidence supports the widely held assumption that conformational heterogeneity promotes functional promiscuity. The common link between these coevolving paradigms is the inherent structural plasticity and conformational dynamics of proteins that, on one hand, lead to complex but evolutionarily selected energy landscapes and, on the other hand, promote functional promiscuity. Here we consider a logical extension of the overlap between these two nascent paradigms: functionally promiscuous and multifunctional enzymes such as detoxification enzymes are expected to have an ensemble landscape with more states accessible on multiple time scales than substrate specific enzymes. Two attributes of detoxification enzymes become important in the context of conformational ensembles: these enzymes metabolize multiple substrates, often in substrate mixtures, and they can form multiple products from a single substrate. These properties, combined with complex conformational landscapes, lead to the possibility of interesting time-dependent, or emergent, properties. Here we demonstrate these properties with kinetic simulations of nonequilibrium steady state (NESS) behavior resulting from energy landscapes expected for detoxification enzymes. Analogous scenarios with other promiscuous enzymes may be worthy of consideration.
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Affiliation(s)
- William M Atkins
- Department of Medicinal Chemistry and Department of Applied Mathematics, University of Washington, Seattle, Washington 98190, United States.
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39
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Balogh LM, Atkins WM. Interactions of glutathione transferases with 4-hydroxynonenal. Drug Metab Rev 2011; 43:165-78. [PMID: 21401344 DOI: 10.3109/03602532.2011.558092] [Citation(s) in RCA: 263] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Electrophilic products of lipid peroxidation are important contributors to the progression of several pathological states. The prototypical α,β-unsaturated aldehyde, 4-hydroxynonenal (HNE), triggers cellular events associated with oxidative stress, which can be curtailed by the glutathione-dependent elimination of HNE. The glutathione transferases (GSTs) are a major determinate of the intracellular concentration of HNE and can influence susceptibility to toxic effects, particularly when HNE and GST levels are altered in disease states. In this article, we provide a brief summary of the cellular effects of HNE, followed by a review of its GST-catalyzed detoxification, with an emphasis on the structural attributes that play an important role in the interactions with alpha-class GSTs. Some of the key determining characteristics that impart high alkenal activity reside in the unique C-terminal interactions of the GSTA4-4 enzyme. Studies encompassing both kinetic and structural analyses of related isoforms will be highlighted, with additional attention to stereochemical aspects that demonstrate the capacity of GSTA4-4 to detoxify both enantiomers of the biologically relevant racemic mixture while generating a select set of diastereomeric products with subsequent implications. A summary of the literature that examines the interplay between GSTs and HNE in model systems relevant to oxidative stress will also be discussed to demonstrate the magnitude of importance of GSTs in the overall detoxification scheme.
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Affiliation(s)
- Larissa M Balogh
- Department of Pharmacokinetics, Dynamics, and Metabolism, Pfizer Global Research and Development, Pfizer Inc., Groton, CT 06340, USA.
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40
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Balchin D, Fanucchi S, Achilonu I, Adamson RJ, Burke J, Fernandes M, Gildenhuys S, Dirr HW. Stability of the domain interface contributes towards the catalytic function at the H-site of class alpha glutathione transferase A1-1. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1804:2228-33. [DOI: 10.1016/j.bbapap.2010.09.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 08/26/2010] [Accepted: 09/02/2010] [Indexed: 11/25/2022]
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41
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Shireman LM, Kripps KA, Balogh LM, Conner KP, Whittington D, Atkins WM. Glutathione transferase A4-4 resists adduction by 4-hydroxynonenal. Arch Biochem Biophys 2010; 504:182-9. [PMID: 20836986 DOI: 10.1016/j.abb.2010.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 09/06/2010] [Accepted: 09/08/2010] [Indexed: 12/30/2022]
Abstract
4-Hydroxy-2-trans-nonenal (HNE) is a lipid peroxidation product that contributes to the pathophysiology of several diseases with components of oxidative stress. The electrophilic nature of HNE results in covalent adduct formation with proteins, fatty acids and DNA. However, it remains unclear whether enzymes that metabolize HNE avoid inactivation by it. Glutathione transferase A4-4 (GST A4-4) plays a significant role in the elimination of HNE by conjugating it with glutathione (GSH), with catalytic activity toward HNE that is dramatically higher than the homologous GST A1-1 or distantly related GSTs. To determine whether enzymes that metabolize HNE resist its covalent adduction, the rates of adduction of these GST isoforms were compared and the functional effects of adduction on catalytic properties were determined. Although GST A4-4 and GST A1-1 have striking structural similarity, GST A4-4 was insensitive to adduction by HNE under conditions that yield modest adduction of GST A1-1 and extensive adduction of GST P1-1. Furthermore, adduction of GST P1-1 by HNE eliminated its activity toward the substrates 1-chloro-2,4-dinitrobenzene (CDNB) and toward HNE itself. HNE effects on GST A4-4 and A1-1 were less significant. The results indicate that enzymes that metabolize HNE may have evolved structurally to resist covalent adduction by it.
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Affiliation(s)
- Laura M Shireman
- Department of Medicinal Chemistry, University of Washington, Seattle, 98195-7610, USA
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Porcine glutathione transferase Alpha 2-2 is a human GST A3-3 analogue that catalyses steroid double-bond isomerization. Biochem J 2010; 431:159-67. [DOI: 10.1042/bj20100839] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A primary role of GSTs (glutathione transferases) is detoxication of electrophilic compounds. In addition to this protective function, hGST (human GST) A3-3, a member of the Alpha class of soluble GSTs, has prominent steroid double-bond isomerase activity. The isomerase reaction is an obligatory step in the biosynthesis of steroid hormones, indicating a special role of hGST A3-3 in steroidogenic tissues. An analogous GST with high steroid isomerase activity has so far not been found in any other biological species. In the present study, we characterized a Sus scrofa (pig) enzyme, pGST A2-2, displaying high steroid isomerase activity. High levels of pGST A2-2 expression were found in ovary, testis and liver. In its functional properties, other than steroid isomerization, pGST A2-2 was most similar to hGST A3-3. The properties of the novel porcine enzyme lend support to the notion that particular GSTs play an important role in steroidogenesis.
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Abstract
Many, if not most, enzymes can promiscuously catalyze reactions, or act on substrates, other than those for which they evolved. Here, we discuss the structural, mechanistic, and evolutionary implications of this manifestation of infidelity of molecular recognition. We define promiscuity and related phenomena and also address their generality and physiological implications. We discuss the mechanistic enzymology of promiscuity--how enzymes, which generally exert exquisite specificity, catalyze other, and sometimes barely related, reactions. Finally, we address the hypothesis that promiscuous enzymatic activities serve as evolutionary starting points and highlight the unique evolutionary features of promiscuous enzyme functions.
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Affiliation(s)
- Olga Khersonsky
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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44
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Balogh LM, Le Trong I, Kripps KA, Shireman LM, Stenkamp RE, Zhang W, Mannervik B, Atkins WM. Substrate specificity combined with stereopromiscuity in glutathione transferase A4-4-dependent metabolism of 4-hydroxynonenal. Biochemistry 2010; 49:1541-8. [PMID: 20085333 DOI: 10.1021/bi902038u] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Conjugation to glutathione (GSH) by glutathione transferase A4-4 (GSTA4-4) is a major route of elimination for the lipid peroxidation product 4-hydroxynonenal (HNE), a toxic compound that contributes to numerous diseases. Both enantiomers of HNE are presumed to be toxic, and GSTA4-4 has negligible stereoselectivity toward them, despite its high catalytic chemospecificity for alkenals. In contrast to the highly flexible, and substrate promiscuous, GSTA1-1 isoform that has poor catalytic efficiency with HNE, GSTA4-4 has been postulated to be a rigid template that is preorganized for HNE metabolism. However, the combination of high substrate chemoselectivity and low substrate stereoselectivity is intriguing. The mechanism by which GSTA4-4 achieves this combination is important, because it must metabolize both enantiomers of HNE to efficiently detoxify the biologically formed mixture. The crystal structures of GSTA4-4 and an engineered variant of GSTA1-1 with high catalytic efficiency toward HNE, cocrystallized with a GSH-HNE conjugate analogue, demonstrate that GSTA4-4 undergoes no enantiospecific induced fit; instead, the active site residue Arg15 is ideally located to interact with the 4-hydroxyl group of either HNE enantiomer. The results reveal an evolutionary strategy for achieving biologically useful stereopromiscuity toward a toxic racemate, concomitant with high catalytic efficiency and substrate specificity toward an endogenously formed toxin.
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Affiliation(s)
- Larissa M Balogh
- Department of Medicinal Chemistry, Box 357610, University of Washington, Seattle, Washington 98195, USA
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45
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Lan T, Yang ZL, Yang X, Liu YJ, Wang XR, Zeng QY. Extensive functional diversification of the Populus glutathione S-transferase supergene family. THE PLANT CELL 2009; 21:3749-66. [PMID: 19996377 PMCID: PMC2814494 DOI: 10.1105/tpc.109.070219] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 10/31/2009] [Accepted: 11/16/2009] [Indexed: 05/17/2023]
Abstract
Identifying how genes and their functions evolve after duplication is central to understanding gene family radiation. In this study, we systematically examined the functional diversification of the glutathione S-transferase (GST) gene family in Populus trichocarpa by integrating phylogeny, expression, substrate specificity, and enzyme kinetic data. GSTs are ubiquitous proteins in plants that play important roles in stress tolerance and detoxification metabolism. Genome annotation identified 81 GST genes in Populus that were divided into eight classes with distinct divergence in their evolutionary rate, gene structure, expression responses to abiotic stressors, and enzymatic properties of encoded proteins. In addition, when all the functional parameters were examined, clear divergence was observed within tandem clusters and between paralogous gene pairs, suggesting that subfunctionalization has taken place among duplicate genes. The two domains of GST proteins appear to have evolved under differential selective pressures. The C-terminal domain seems to have been subject to more relaxed functional constraints or divergent directional selection, which may have allowed rapid changes in substrate specificity, affinity, and activity, while maintaining the primary function of the enzyme. Our findings shed light on mechanisms that facilitate the retention of duplicate genes, which can result in a large gene family with a broad substrate spectrum and a wide range of reactivity toward different substrates.
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Affiliation(s)
- Ting Lan
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate School, Chinese Academy of Sciences, Beijing 100049, China
| | - Zhi-Ling Yang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate School, Chinese Academy of Sciences, Beijing 100049, China
| | - Xue Yang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate School, Chinese Academy of Sciences, Beijing 100049, China
| | - Yan-Jing Liu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xiao-Ru Wang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Department of Ecology and Environmental Science, Umeå Plant Science Centre, Umeå University, SE-901 87 Umeå, Sweden
| | - Qing-Yin Zeng
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Address correspondence to
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46
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Balogh LM, Le Trong I, Kripps KA, Tars K, Stenkamp RE, Mannervik B, Atkins WM. Structural analysis of a glutathione transferase A1-1 mutant tailored for high catalytic efficiency with toxic alkenals. Biochemistry 2009; 48:7698-704. [PMID: 19618965 DOI: 10.1021/bi900895b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The specificity of human glutathione transferase (GST) A1-1 is drastically altered to favor alkenal substrates in the GIMFhelix mutant designed to mimic first-sphere interactions utilized by GSTA4-4. This redesign serves as a model for improving our understanding of the structural determinants that contribute to the distinct specificities of alpha class GSTs. Herein we report the first crystal structures of GIMFhelix, both in complex with GSH and in apo form at 1.98 and 2.38 A resolution. In contrast to the preorganized hydrophobic binding pocket that accommodates alkenals in GSTA4-4, GSTA1-1 includes a dynamic alpha9 helix that undergoes a ligand-dependent localization to complete the active site. Comparisons of the GIMFhelix structures with previously reported structures show a striking similarity with the GSTA4-4 active site obtained within an essentially GSTA1-1 scaffold and reveal the alpha9 helix assumes a similar localized structure regardless of active site occupancy in a manner resembling that of GSTA4-4. However, we cannot fully account for all the structural elements important in GSTA4-4 within the mutant's active site. The contribution of Phe10 to the Tyr212-Phe10-Phe220 network prevents complete C-terminal closure and demonstrates that the presence of Phe10 within the context of a GSTA4-4-like active site may ultimately hinder Phe220, a key C-terminal residue, from effectively contributing to the active site. In total, these results illustrate the remaining structural differences presumably reflected in the previously reported catalytic efficiencies of GIMFhelix and GSTA4-4 and emphasize the F10P mutation as being necessary to completely accomplish the transformation to a highly specific GST from the more promiscuous GSTA1-1 enzyme.
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Affiliation(s)
- Larissa M Balogh
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, USA
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48
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Malmstroem L, Hou L, Atkins WM, Goodlett DR. On the use of hydrogen/deuterium exchange mass spectrometry data to improve de novo protein structure prediction. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2009; 23:459-461. [PMID: 19125403 DOI: 10.1002/rcm.3882] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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49
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Smith AJT, Müller R, Toscano MD, Kast P, Hellinga HW, Hilvert D, Houk KN. Structural reorganization and preorganization in enzyme active sites: comparisons of experimental and theoretically ideal active site geometries in the multistep serine esterase reaction cycle. J Am Chem Soc 2008; 130:15361-73. [PMID: 18939839 DOI: 10.1021/ja803213p] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many enzymes catalyze reactions with multiple chemical steps, requiring the stabilization of multiple transition states during catalysis. Such enzymes must strike a balance between the conformational reorganization required to stabilize multiple transition states of a reaction and the confines of a preorganized active site in the polypeptide tertiary structure. Here we investigate the compromise between structural reorganization during the catalytic process and preorganization of the active site for a multistep enzyme-catalyzed reaction, the hydrolysis of esters by the Ser-His-Asp/Glu catalytic triad. Quantum mechanical transition states were used to generate ensembles of geometries that can catalyze each individual step in the mechanism. These geometries are compared to each other by superpositions of catalytic atoms to find "consensus" geometries that can catalyze all steps with minimal rearrangement. These consensus geometries are found to be excellent matches for the natural active site. Preorganization is therefore found to be the major defining characteristic of the active site, and reorganizational motions often proposed to promote catalysis have been minimized. The variability of enzyme active sites observed by X-ray crystallography was also investigated empirically. A catalog of geometrical parameters relating active site residues to each other and to bound inhibitors was collected from a set of crystal structures. The crystal-structure-derived values were then compared to the ranges found in quantum mechanically optimized structures along the entire reaction coordinate. The empirical ranges are found to encompass the theoretical ranges when thermal fluctuations are taken into account. Therefore, the active sites are preorganized to a geometry that can be objectively and quantitatively defined as minimizing conformational reorganization while maintaining optimal transition state stabilization for every step during catalysis. The results provide a useful guiding principle for de novo design of enzymes with multistep mechanisms.
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Affiliation(s)
- Adam J T Smith
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
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50
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Balogh LM, Roberts AG, Shireman LM, Greene RJ, Atkins WM. The stereochemical course of 4-hydroxy-2-nonenal metabolism by glutathione S-transferases. J Biol Chem 2008; 283:16702-10. [PMID: 18424441 DOI: 10.1074/jbc.m801725200] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
4-Hydroxy-2-nonenal (HNE) is a toxic aldehyde generated during lipid peroxidation and has been implicated in a variety of pathological states associated with oxidative stress. Glutathione S-transferase (GST) A4-4 is recognized as one of the predominant enzymes responsible for the metabolism of HNE. However, substrate and product stereoselectivity remain to be fully explored. The results from a product formation assay indicate that hGSTA4-4 exhibits a modest preference for the biotransformation of S-HNE in the presence of both enantiomers. Liquid chromatography mass spectrometry analyses using the racemic and enantioisomeric HNE substrates explicitly demonstrate that hGSTA4-4 conjugates glutathione to both HNE enantiomers in a completely stereoselective manner that is not maintained in the spontaneous reaction. Compared with other hGST isoforms, hGSTA4-4 shows the highest degree of stereoselectivity. NMR experiments in combination with simulated annealing structure determinations enabled the determination of stereochemical configurations for the GSHNE diastereomers and are consistent with an hGSTA4-4-catalyzed nucleophilic attack that produces only the S-configuration at the site of conjugation, regardless of substrate chirality. In total these results indicate that hGSTA4-4 exhibits an intriguing combination of low substrate stereoselectivity with strict product stereoselectivity. This behavior allows for the detoxification of both HNE enantiomers while generating only a select set of GSHNE diastereomers with potential stereochemical implications concerning their effects and fates in biological tissues.
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Affiliation(s)
- Larissa M Balogh
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195-7610, USA
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