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Tang J, Yao J, Pan D, Huang J, Wang J, Li QX, Dong F, Wu X. Characterization and catalytic mechanism of a direct demethylsulfide hydrolase for catabolism of the methylthiol-s-triazine prometryn. JOURNAL OF HAZARDOUS MATERIALS 2023; 446:130708. [PMID: 36608577 DOI: 10.1016/j.jhazmat.2022.130708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/12/2022] [Accepted: 12/28/2022] [Indexed: 06/17/2023]
Abstract
Demethylthio is one of the most important ways for microorganisms to metabolize triazine herbicides. Previous studies have found that the initial reaction of prometryn catabolism in Leucobacter triazinivorans JW-1 was the hydroxylation of its methylthio group, however, the corresponding functional enzyme was not yet clear. In this study, the gene proA was responsible for the initial step of prometryn catabolism from the strain JW-1 was cloned and expressed, and the purified amidohydrolases ProA have the ability to transform prometryn to 2-hydroxypropazine and methanethiol. The optimized reaction temperature and pH of ProA were 45 °C and 7.0, respectively, and the kinetic constants Km and Vmax of ProA for the catalysis of prometryn were 32.6 μM and 0.09 μmol/min/mg, respectively. Molecular docking analyses revealed that different catalysis efficiency of ProA and TrzN (Nocardioides sp. C190) for prometryn and atrazine was due to non-covalent changes in amino acid residues. Our findings provide new insights into the understanding of s-triazine catabolism at the molecular level.
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Affiliation(s)
- Jun Tang
- College of Resources and Environment, Anhui Agricultural University, Key Laboratory of Agri-food Safety of Anhui Province, Hefei 230036, China
| | - Jinjin Yao
- College of Resources and Environment, Anhui Agricultural University, Key Laboratory of Agri-food Safety of Anhui Province, Hefei 230036, China
| | - Dandan Pan
- College of Resources and Environment, Anhui Agricultural University, Key Laboratory of Agri-food Safety of Anhui Province, Hefei 230036, China
| | - Junwei Huang
- College of Resources and Environment, Anhui Agricultural University, Key Laboratory of Agri-food Safety of Anhui Province, Hefei 230036, China
| | - Jie Wang
- College of Resources and Environment, Anhui Agricultural University, Key Laboratory of Agri-food Safety of Anhui Province, Hefei 230036, China
| | - Qing X Li
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, 1955 East-West Road, Honolulu, HI 96822, USA
| | - Fengshou Dong
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiangwei Wu
- College of Resources and Environment, Anhui Agricultural University, Key Laboratory of Agri-food Safety of Anhui Province, Hefei 230036, China.
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2
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Chen D, Li Y, Li X, Savidge T, Qian Y, Fan X. Factors determining the enzyme catalytic power caused by noncovalent interactions: Charge alterations in enzyme active sites. ARAB J CHEM 2022. [DOI: 10.1016/j.arabjc.2021.103611] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Chen D, Li Y, Li X, Hong X, Fan X, Savidge T. Key difference between transition state stabilization and ground state destabilization: increasing atomic charge densities before or during enzyme–substrate binding. Chem Sci 2022; 13:8193-8202. [PMID: 35919436 PMCID: PMC9278421 DOI: 10.1039/d2sc01994a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 06/20/2022] [Indexed: 11/21/2022] Open
Abstract
The origin of the enormous catalytic power of enzymes has been extensively studied through experimental and computational approaches. Although precise mechanisms are still subject to much debate, enzymes are thought to catalyze reactions by stabilizing transition states (TSs) or destabilizing ground states (GSs). By exploring the catalysis of various types of enzyme–substrate noncovalent interactions, we found that catalysis by TS stabilization and the catalysis by GS destabilization share common features by reducing the free energy barriers (ΔG‡s) of reactions, but are different in attaining the requirement for ΔG‡ reduction. Irrespective of whether enzymes catalyze reactions by TS stabilization or GS destabilization, they reduce ΔG‡s by enhancing the charge densities of catalytic atoms that experience a reduction in charge density between GSs and TSs. Notably, in TS stabilization, the charge density of catalytic atoms is enhanced prior to enzyme–substrate binding; whereas in GS destabilization, the charge density of catalytic atoms is enhanced during the enzyme–substrate binding. Results show that TS stabilization and GS destabilization are not contradictory to each other and are consistent in reducing the ΔG‡s of reactions. The full mechanism of enzyme catalysis includes the mechanism of reducing ΔG‡ and the mechanism of enhancing atomic charge densities. Our findings may help resolve the debate between TS stabilization and GS destabilization and assist our understanding of catalysis and the design of artificial enzymes. Transition state stabilization and ground state destabilization utilize the same molecular mechanism when lowering the free energy barriers (ΔG‡s) of reactions, but differ in achieving the requirement for ΔG‡ reduction.![]()
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Affiliation(s)
- Deliang Chen
- Jiangxi Key Laboratory of Organo-Pharmaceutical Chemistry, Chemistry and Chemical Engineering College, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Yibao Li
- Jiangxi Key Laboratory of Organo-Pharmaceutical Chemistry, Chemistry and Chemical Engineering College, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Xun Li
- Jiangxi Key Laboratory of Organo-Pharmaceutical Chemistry, Chemistry and Chemical Engineering College, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Xuechuan Hong
- State Key Laboratory of Virology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery and Hubei Province, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China
| | - Xiaolin Fan
- Jiangxi Key Laboratory of Organo-Pharmaceutical Chemistry, Chemistry and Chemical Engineering College, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Tor Savidge
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030, USA
- Texas Children's Microbiome Center, Texas Childrens Hospital, Houston, TX 77030, USA
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Truong DP, Rousseau S, Machala BW, Huddleston JP, Zhu M, Hull KG, Romo D, Raushel FM, Sacchettini JC, Glasner ME. Second-Shell Amino Acid R266 Helps Determine N-Succinylamino Acid Racemase Reaction Specificity in Promiscuous N-Succinylamino Acid Racemase/ o-Succinylbenzoate Synthase Enzymes. Biochemistry 2021; 60:3829-3840. [PMID: 34845903 DOI: 10.1021/acs.biochem.1c00627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Catalytic promiscuity is the coincidental ability to catalyze nonbiological reactions in the same active site as the native biological reaction. Several lines of evidence show that catalytic promiscuity plays a role in the evolution of new enzyme functions. Thus, studying catalytic promiscuity can help identify structural features that predispose an enzyme to evolve new functions. This study identifies a potentially preadaptive residue in a promiscuous N-succinylamino acid racemase/o-succinylbenzoate synthase (NSAR/OSBS) enzyme from Amycolatopsis sp. T-1-60. This enzyme belongs to a branch of the OSBS family which includes many catalytically promiscuous NSAR/OSBS enzymes. R266 is conserved in all members of the NSAR/OSBS subfamily. However, the homologous position is usually hydrophobic in other OSBS subfamilies, whose enzymes lack NSAR activity. The second-shell amino acid R266 is close to the catalytic acid/base K263, but it does not contact the substrate, suggesting that R266 could affect the catalytic mechanism. Mutating R266 to glutamine in Amycolatopsis NSAR/OSBS profoundly reduces NSAR activity but moderately reduces OSBS activity. This is due to a 1000-fold decrease in the rate of proton exchange between the substrate and the general acid/base catalyst K263. This mutation is less deleterious for the OSBS reaction because K263 forms a cation-π interaction with the OSBS substrate and/or the intermediate, rather than acting as a general acid/base catalyst. Together, the data explain how R266 contributes to NSAR reaction specificity and was likely an essential preadaptation for the evolution of NSAR activity.
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Affiliation(s)
- Dat P Truong
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, United States
| | - Simon Rousseau
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, United States
| | - Benjamin W Machala
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, United States
| | - Jamison P Huddleston
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843-3255, United States
| | - Mingzhao Zhu
- Baylor Synthesis and Drug-Lead Discovery Laboratory, Department of Chemistry and Biochemistry, Baylor University, One Bear Place, Waco, Texas 76798-7348, United States
| | - Kenneth G Hull
- Baylor Synthesis and Drug-Lead Discovery Laboratory, Department of Chemistry and Biochemistry, Baylor University, One Bear Place, Waco, Texas 76798-7348, United States
| | - Daniel Romo
- Baylor Synthesis and Drug-Lead Discovery Laboratory, Department of Chemistry and Biochemistry, Baylor University, One Bear Place, Waco, Texas 76798-7348, United States
| | - Frank M Raushel
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, United States.,Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843-3255, United States
| | - James C Sacchettini
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843-3255, United States
| | - Margaret E Glasner
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, United States
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Abstract
Ufmylation is a post-translational modification essential for regulating key cellular processes. A three-enzyme cascade involving E1, E2 and E3 is required for UFM1 attachment to target proteins. How UBA5 (E1) and UFC1 (E2) cooperatively activate and transfer UFM1 is still unclear. Here, we present the crystal structure of UFC1 bound to the C-terminus of UBA5, revealing how UBA5 interacts with UFC1 via a short linear sequence, not observed in other E1-E2 complexes. We find that UBA5 has a region outside the adenylation domain that is dispensable for UFC1 binding but critical for UFM1 transfer. This region moves next to UFC1’s active site Cys and compensates for a missing loop in UFC1, which exists in other E2s and is needed for the transfer. Overall, our findings advance the understanding of UFM1’s conjugation machinery and may serve as a basis for the development of ufmylation inhibitors. Ufmylation is a well-established ubiquitin-like protein modification, but its mechanism is largely unclear. Here, the authors present a crystal structure of the ufmylation-specific E1-E2 complex, revealing differences to the ubiquitination machinery and mechanistic details of the ufmylation process.
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Evolution of cyclohexadienyl dehydratase from an ancestral solute-binding protein. Nat Chem Biol 2018; 14:542-547. [PMID: 29686357 DOI: 10.1038/s41589-018-0043-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 03/01/2018] [Indexed: 11/09/2022]
Abstract
The emergence of enzymes through the neofunctionalization of noncatalytic proteins is ultimately responsible for the extraordinary range of biological catalysts observed in nature. Although the evolution of some enzymes from binding proteins can be inferred by homology, we have a limited understanding of the nature of the biochemical and biophysical adaptations along these evolutionary trajectories and the sequence in which they occurred. Here we reconstructed and characterized evolutionary intermediate states linking an ancestral solute-binding protein to the extant enzyme cyclohexadienyl dehydratase. We show how the intrinsic reactivity of a desolvated general acid was harnessed by a series of mutations radiating from the active site, which optimized enzyme-substrate complementarity and transition-state stabilization and minimized sampling of noncatalytic conformations. Our work reveals the molecular evolutionary processes that underlie the emergence of enzymes de novo, which are notably mirrored by recent examples of computational enzyme design and directed evolution.
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Robinson AC, Schlessman JL, García-Moreno E B. Dielectric Properties of a Protein Probed by Reversal of a Buried Ion Pair. J Phys Chem B 2018; 122:2516-2524. [PMID: 29466010 DOI: 10.1021/acs.jpcb.7b12121] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Thirty years ago, Hwang and Warshel suggested that a microenvironment preorganized to stabilize an ion pair would be incapable of reorganizing to stabilize the reverse ion pair. The implications were that (1) proteins have a limited capacity to reorganize, even under the influence of strong interactions, such as those present when ionizable groups are buried in the hydrophobic interior of a protein, and (2) the inability of proteins to tolerate the reversal of buried ion pairs demonstrates the limitations inherent to continuum electrostatic models of proteins. Previously we showed that when buried individually in the interior of staphylococcal nuclease, Glu23 and Lys36 have p Ka values near pH 7, but when buried simultaneously, they establish a strong interaction of ∼5 kcal/mol and have p Ka values shifted toward more normal values. Here, using equilibrium thermodynamic measurements, crystal structures, and NMR spectroscopy experiments, we show that although the reversed, individual substitutions-Lys23 and Glu36-also have p Ka values near 7, when buried together, they neither establish a strong interaction nor promote reorganization of their microenvironment. These experiments both confirm Warshel's original hypothesis and expand it by showing that it applies to reorganization, as demonstrated by our artificial ion pairs, as well as to preorganization as is commonly argued for motifs that stabilize naturally occurring ion pairs in polar microenvironments. These data constitute a challenging benchmark useful to test the ability of structure-based algorithms to reproduce the compensation between self-energy, Coulomb and polar interactions in hydrophobic environments of proteins.
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Affiliation(s)
- Aaron C Robinson
- Department of Biophysics , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Jamie L Schlessman
- Chemistry Department , U.S. Naval Academy , Annapolis , Maryland 21402 , United States
| | - Bertrand García-Moreno E
- Department of Biophysics , Johns Hopkins University , Baltimore , Maryland 21218 , United States
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Esquirol L, Peat TS, Wilding M, Lucent D, French NG, Hartley CJ, Newman J, Scott C. Structural and biochemical characterization of the biuret hydrolase (BiuH) from the cyanuric acid catabolism pathway of Rhizobium leguminasorum bv. viciae 3841. PLoS One 2018; 13:e0192736. [PMID: 29425231 PMCID: PMC5806882 DOI: 10.1371/journal.pone.0192736] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 01/29/2018] [Indexed: 11/24/2022] Open
Abstract
Biuret deamination is an essential step in cyanuric acid mineralization. In the well-studied atrazine degrading bacterium Pseudomonas sp. strain ADP, the amidase AtzE catalyzes this step. However, Rhizobium leguminosarum bv. viciae 3841 uses an unrelated cysteine hydrolase, BiuH, instead. Herein, structures of BiuH, BiuH with bound inhibitor and variants of BiuH are reported. The substrate is bound in the active site by a hydrogen bonding network that imparts high substrate specificity. The structure of the inactive Cys175Ser BiuH variant with substrate bound in the active site revealed that an active site cysteine (Cys175), aspartic acid (Asp36) and lysine (Lys142) form a catalytic triad, which is consistent with biochemical studies of BiuH variants. Finally, molecular dynamics simulations highlighted the presence of three channels from the active site to the enzyme surface: a persistent tunnel gated by residues Val218 and Gln215 forming a potential substrate channel and two smaller channels formed by Val28 and a mobile loop (including residues Phe41, Tyr47 and Met51) that may serve as channels for co-product (ammonia) or co-substrate (water).
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Affiliation(s)
- Lygie Esquirol
- CSIRO Biocatalysis and Synthetic Biology, Canberra, Australian Capital Territory, Australia
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Thomas S. Peat
- CSIRO Biomedical Manufacturing, Parkville, Melbourne, Victoria, Australia
| | - Matthew Wilding
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory, Australia
- CSIRO Biomedical Manufacturing, Parkville, Melbourne, Victoria, Australia
| | - Del Lucent
- Department of Electrical Engineering and Physics, Wilkes University, Wilkes-Barre, Pennsylvania, United States of America
| | - Nigel G. French
- CSIRO Biocatalysis and Synthetic Biology, Canberra, Australian Capital Territory, Australia
| | - Carol J. Hartley
- CSIRO Biocatalysis and Synthetic Biology, Canberra, Australian Capital Territory, Australia
| | - Janet Newman
- CSIRO Biomedical Manufacturing, Parkville, Melbourne, Victoria, Australia
| | - Colin Scott
- CSIRO Biocatalysis and Synthetic Biology, Canberra, Australian Capital Territory, Australia
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Sugrue E, Scott C, Jackson CJ. Constrained evolution of a bispecific enzyme: lessons for biocatalyst design. Org Biomol Chem 2017; 15:937-946. [DOI: 10.1039/c6ob02355j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Analysis of the natural evolution of bispecificity in triazine hydrolase highlights the importance of epistasis in protein engineering and evolution.
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Affiliation(s)
- E. Sugrue
- Research School of Chemistry
- Australian National University
- Canberra
- Australia
| | - C. Scott
- Commonwealth Scientific and Industrial Research Organisation
- Canberra
- Australia
| | - C. J. Jackson
- Research School of Chemistry
- Australian National University
- Canberra
- Australia
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