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Bearne SL. Design and evaluation of substrate-product analog inhibitors for racemases and epimerases utilizing a 1,1-proton transfer mechanism. Methods Enzymol 2023; 690:397-444. [PMID: 37858537 DOI: 10.1016/bs.mie.2023.06.014] [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] [Indexed: 10/21/2023]
Abstract
Racemases and epimerases catalyze the inversion of stereochemistry at asymmetric carbon atoms to generate stereoisomers that often play important roles in normal and pathological physiology. Consequently, there is interest in developing inhibitors of these enzymes for drug discovery. A strategy for the rational design of substrate-product analog (SPA) inhibitors of racemases and epimerases utilizing a direct 1,1-proton transfer mechanism is elaborated. This strategy assumes that two groups on the asymmetric carbon atom remain fixed at active-site binding determinants, while the hydrogen and third, motile group move during catalysis, with the latter potentially traveling between an R- and S-pocket at the active site. SPAs incorporate structural features of the substrate and product, often with geminal disubstitution on the asymmetric carbon atom to simultaneously present the motile group to both the R- and S-pockets. For racemases operating on substrates bearing three polar groups (glutamate, aspartate, and serine racemases) or with compact, hydrophobic binding pockets (proline racemase), substituent motion is limited and the design strategy furnishes inhibitors with poor or modest binding affinities. The approach is most successful when substrates have a large, motile hydrophobic group that binds at a plastic and/or capacious hydrophobic site. Potent inhibitors were developed for mandelate racemase, isoleucine epimerase, and α-methylacyl-CoA racemase using the SPA inhibitor design strategy, exhibiting binding affinities ranging from substrate-like to exceeding that of the substrate by 100-fold. This rational approach for designing inhibitors of racemases and epimerases having the appropriate active-site architectures is a useful strategy for furnishing compounds for drug development.
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Affiliation(s)
- Stephen L Bearne
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada; Department of Chemistry, Dalhousie University, Halifax, NS, Canada.
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Bearne SL, Hayden JA. Application of circular dichroism-based assays to racemases and epimerases: Recognition and catalysis of reactions of chiral substrates by mandelate racemase. Methods Enzymol 2023; 685:127-169. [PMID: 37245900 DOI: 10.1016/bs.mie.2023.03.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Racemases and epimerases have attracted much interest because of their astonishing ability to catalyze the rapid α-deprotonation of carbon acid substrates with high pKa values (∼13-30) leading to the formation of d-amino acids or various carbohydrate diastereomers that serve important roles in both normal physiology and pathology. Enzymatic assays to measure the initial rates of reactions catalyzed by these enzymes are discussed using mandelate racemase (MR) as an example. For MR, a convenient, rapid, and versatile circular dichroism (CD)-based assay has been used to determine the kinetic parameters accompanying the MR-catalyzed racemization of mandelate and alternative substrates. This direct, continuous assay permits real time monitoring of reaction progress, the rapid determination of initial velocities, and immediate recognition of anomalous behaviors. MR recognizes chiral substrates primarily through interactions of the phenyl ring of (R)- or (S)-mandelate with the hydrophobic R- or S-pocket at the active site, respectively. During catalysis, the carboxylate and α-hydroxyl groups of the substrate remain fixed in place through interactions with the Mg2+ ion and multiple H-bonding interactions, while the phenyl ring moves between the R- and S-pockets. The minimal requirements for the substrate appear to be the presence of a glycolate or glycolamide moiety, and a hydrophobic group of limited size that can stabilize the carbanionic intermediate through resonance or strong inductive effects. Similar CD-based assays may be applied to determine the activity of other racemases or epimerases with proper consideration of the molar ellipticity, wavelength, overall absorbance of the sample, and the light pathlength.
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Affiliation(s)
- Stephen L Bearne
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada; Department of Chemistry, Dalhousie University, Halifax, NS, Canada.
| | - Joshua A Hayden
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
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Tang CD, Zhang X, Shi HL, Liu XX, Wang HY, Lu YF, Zhang SP, Kan YC, Yao LG. Improving catalytic activity of Lactobacillus harbinensis -mandelate dehydrogenase toward -o-chloromandelic acid by laboratory evolution. MOLECULAR CATALYSIS 2022. [DOI: 10.1016/j.mcat.2022.112700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Wang Q, Geng S, Wang L, Wen Z, Sun X, Huang H. Bacterial mandelic acid degradation pathway and its application in biotechnology. J Appl Microbiol 2022; 133:273-286. [PMID: 35294082 DOI: 10.1111/jam.15529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 12/22/2021] [Accepted: 03/09/2022] [Indexed: 11/28/2022]
Abstract
Mandelic acid and its derivatives are an important class of chemical synthetic blocks, which is widely used in drug synthesis and stereochemistry research. In nature, mandelic acid degradation pathway has been widely identified and analyzed as a representative pathway of aromatic compounds degradation. The most studied mandelic acid degradation pathway from Pseudomonas putida consists of mandelate racemase, S-mandelate dehydrogenase, benzoylformate decarboxylase, benzaldehyde dehydrogenase and downstream benzoic acid degradation pathways. Because of the ability to catalyze various reactions of aromatic substrates, pathway enzymes have been widely used in biocatalysis, kinetic resolution, chiral compounds synthesis or construction of new metabolic pathways. In this paper, the physiological significance and the existing range of the mandelic acid degradation pathway were introduced first. Then each of the enzymes in the pathway is reviewed one by one, including the researches on enzymatic properties and the applications in biotechnology as well as efforts that have been made to modify the substrate specificity or improving catalytic activity by enzyme engineering to adapt different applications. The composition of the important metabolic pathway of bacterial mandelic acid degradation pathway as well as the researches and applications of pathway enzymes is summarized in this review for the first time.
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Affiliation(s)
- Qingzhuo Wang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2# Xuelin Road, Qixia District, Nanjing, People's Republic of China
| | - Shanshan Geng
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2# Xuelin Road, Qixia District, Nanjing, People's Republic of China
| | - Lingru Wang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2# Xuelin Road, Qixia District, Nanjing, People's Republic of China
| | - Zhiqiang Wen
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2# Xuelin Road, Qixia District, Nanjing, People's Republic of China
| | - Xiaoman Sun
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2# Xuelin Road, Qixia District, Nanjing, People's Republic of China
| | - He Huang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2# Xuelin Road, Qixia District, Nanjing, People's Republic of China.,College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, People's Republic of China
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Wang HY, Xie YL, Shi X, Shi HL, Xu JH, Tang CD, Yao LG, Kan YC. Directed evolution of a D-mandelate dehydrogenase toward D-o-chloromandelic acid and insight into the molecular basis for its catalytic performance. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2020.107863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Gu J, Tong H, Sun L, Lin Z. Molecular dynamics perspective on the thermal stability of mandelate racemase. J Biomol Struct Dyn 2018; 37:383-393. [PMID: 29334318 DOI: 10.1080/07391102.2018.1427631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mandelate racemase from Pseudomonas putida is a promising candidate for the dynamic kinetic resolution of α-hydroxy carboxylic acids. In the present study, the thermal stability of mandelate racemase was investigated through molecular dynamics simulations in the temperature range of 303-363 K, which can guide the design of mandelate racemase with higher stability. The basic features such as radius of gyration, surface accessibility, and secondary structure content suggested the instability of mandelate racemase at high temperatures. With increase in temperature, α-helix content reduced significantly, especially the α-helices exposed to the environment. At the simulation time scale considered, intra-protein hydrogen bonds, hydrogen bonds between protein and water decreased at 363 K, while the number of salt-bridges increased. The long-distance networks remarkably changed at 363 K. A considerable number of long-lived (percentage existence time higher than 90%) hydrogen bonds and Cα contacts were lost. Root mean square fluctuation analysis revealed regions with high fluctuation, which should be helpful in the reengineering of mandelate racemase for enhanced thermal stability.
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Affiliation(s)
- Jiali Gu
- a College of Life Sciences , Huzhou University , Huzhou , Zhejiang , 313000 , China
| | - Hongfei Tong
- a College of Life Sciences , Huzhou University , Huzhou , Zhejiang , 313000 , China
| | - Laiyu Sun
- a College of Life Sciences , Huzhou University , Huzhou , Zhejiang , 313000 , China
| | - Zhijian Lin
- b Novel Search Center , Zhejiang Institute of Scientific and Technological Information , Hangzhou , Zhejiang , 310052 , China
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Directed evolution of mandelate racemase by a novel high-throughput screening method. Appl Microbiol Biotechnol 2016; 101:1063-1072. [DOI: 10.1007/s00253-016-7790-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 07/24/2016] [Accepted: 08/03/2016] [Indexed: 12/30/2022]
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Insight into the role of halogen bond in the activity of d-mandelate dehydrogenase toward halogenated substrates. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2016.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Kang L, Bai Y, Cai Y, Zheng X. Discovery of novel feruloyl esterase activity of BioH in Escherichia coli BL21(DE3). Biotechnol Lett 2016; 38:1009-13. [DOI: 10.1007/s10529-016-2075-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 03/01/2016] [Indexed: 12/01/2022]
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