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Serafim LF, Jayasinghe-Arachchige VM, Wang L, Rathee P, Yang J, Moorkkannur N S, Prabhakar R. Distinct chemical factors in hydrolytic reactions catalyzed by metalloenzymes and metal complexes. Chem Commun (Camb) 2023. [PMID: 37366367 DOI: 10.1039/d3cc01380d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
The selective hydrolysis of the extremely stable phosphoester, peptide and ester bonds of molecules by bio-inspired metal-based catalysts (metallohydrolases) is required in a wide range of biological, biotechnological and industrial applications. Despite the impressive advances made in the field, the ultimate goal of designing efficient enzyme mimics for these reactions is still elusive. Its realization will require a deeper understanding of the diverse chemical factors that influence the activities of both natural and synthetic catalysts. They include catalyst-substrate complexation, non-covalent interactions and the electronic nature of the metal ion, ligand environment and nucleophile. Based on our computational studies, their roles are discussed for several mono- and binuclear metallohydrolases and their synthetic analogues. Hydrolysis by natural metallohydrolases is found to be promoted by a ligand environment with low basicity, a metal bound water and a heterobinuclear metal center (in binuclear enzymes). Additionally, peptide and phosphoester hydrolysis is dominated by two competing effects, i.e. nucleophilicity and Lewis acid activation, respectively. In synthetic analogues, hydrolysis is facilitated by the inclusion of a second metal center, hydrophobic effects, a biological metal (Zn, Cu and Co) and a terminal hydroxyl nucleophile. Due to the absence of the protein environment, hydrolysis by these small molecules is exclusively influenced by nucleophile activation. The results gleaned from these studies will enhance the understanding of fundamental principles of multiple hydrolytic reactions. They will also advance the development of computational methods as a predictive tool to design more efficient catalysts for hydrolysis, Diels-Alder reaction, Michael addition, epoxide opening and aldol condensation.
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Affiliation(s)
- Leonardo F Serafim
- Department of Chemistry, University of Miami, Coral Gables, FL 33146, USA.
| | | | - Lukun Wang
- Department of Chemistry, University of Miami, Coral Gables, FL 33146, USA.
| | - Parth Rathee
- Department of Chemistry, University of Miami, Coral Gables, FL 33146, USA.
| | - Jiawen Yang
- Department of Chemistry, University of Miami, Coral Gables, FL 33146, USA.
| | | | - Rajeev Prabhakar
- Department of Chemistry, University of Miami, Coral Gables, FL 33146, USA.
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2
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Norjmaa G, Solé-Daura A, Besora M, Ricart JM, Carbó JJ. Peptide Hydrolysis by Metal (Oxa)cyclen Complexes: Revisiting the Mechanism and Assessing Ligand Effects. Inorg Chem 2021; 60:807-815. [PMID: 33411534 DOI: 10.1021/acs.inorgchem.0c02859] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The mechanism responsible for peptide bond hydrolysis by Co(III) and Cu(II) complexes with (oxa)cyclen ligands has been revisited by means of computational tools. We propose that the mechanism starts by substrate coordination and an outer-sphere attack on the amide C atom of a solvent water molecule assisted by the metal hydroxo moiety as a general base, which occurs through six-membered ring transition states. This new mechanism represents a more likely scenario than the previously proposed mechanisms that involved an inner-sphere nucleophilic attack through more strained four-membered rings transition states. The corresponding computed overall free-energy barrier of 25.2 kcal mol-1 for hydrolysis of the peptide bond in Phe-Ala by a cobalt(III) oxacyclen catalyst (1) is consistent with the experimental values obtained from rate constants. Also, we assessed the influence of the nature of the ligand throughout a systematic replacement of N by O atoms in the (oxa)cyclen ligand. Increasing the number of coordinating O atoms accelerates the reaction by increasing the Lewis acidity of the metal ion. On the other hand, the higher reactivity observed for the copper(II) oxacyclen catalyst with respect to the analogous Co(III) complex can be attributed to the larger Brönsted basicity of the copper(II) hydroxo ligand. Ultimately, the detailed understanding of the ligand and metal nature effects allowed us to identify the double role of the metal hydroxo complexes as Lewis acids and Brönsted bases and to rationalize the observed reactivity trends.
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Affiliation(s)
- Gantulga Norjmaa
- Department de Química Física i Inorgànica, Universitat Rovira i Virgili (URV), Marcel·lí Domingo 1, 43007 Tarragona, Spain
| | - Albert Solé-Daura
- Department de Química Física i Inorgànica, Universitat Rovira i Virgili (URV), Marcel·lí Domingo 1, 43007 Tarragona, Spain
| | - Maria Besora
- Department de Química Física i Inorgànica, Universitat Rovira i Virgili (URV), Marcel·lí Domingo 1, 43007 Tarragona, Spain
| | - Josep M Ricart
- Department de Química Física i Inorgànica, Universitat Rovira i Virgili (URV), Marcel·lí Domingo 1, 43007 Tarragona, Spain
| | - Jorge J Carbó
- Department de Química Física i Inorgànica, Universitat Rovira i Virgili (URV), Marcel·lí Domingo 1, 43007 Tarragona, Spain
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3
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Molnár Á. Synthetic Application of Cyclodextrins in Combination with Metal Ions, Complexes, and Metal Particles. ChemCatChem 2020. [DOI: 10.1002/cctc.202001610] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Árpád Molnár
- Department of Organic Chemistry University of Szeged Dóm tér 8 6720 Szeged Hungary
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4
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Solé-Daura A, Rodríguez-Fortea A, Poblet JM, Robinson D, Hirst JD, Carbó JJ. Origin of Selectivity in Protein Hydrolysis by Zr(IV)-Containing Metal Oxides as Artificial Proteases. ACS Catal 2020. [DOI: 10.1021/acscatal.0c02848] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Albert Solé-Daura
- Department de Quı́mica Fı́sica i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo 1, 43007 Tarragona, Spain
| | - Antonio Rodríguez-Fortea
- Department de Quı́mica Fı́sica i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo 1, 43007 Tarragona, Spain
| | - Josep M. Poblet
- Department de Quı́mica Fı́sica i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo 1, 43007 Tarragona, Spain
| | - David Robinson
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
- Department of Chemistry and Forensics, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, United Kingdom
| | - Jonathan D. Hirst
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Jorge J. Carbó
- Department de Quı́mica Fı́sica i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo 1, 43007 Tarragona, Spain
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Thompson Z, Cowan JA. Artificial Metalloenzymes: Recent Developments and Innovations in Bioinorganic Catalysis. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2000392. [PMID: 32372559 DOI: 10.1002/smll.202000392] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 03/02/2020] [Accepted: 03/09/2020] [Indexed: 06/11/2023]
Abstract
Cellular life is orchestrated by the biochemical components of cells that include nucleic acids, lipids, carbohydrates, proteins, and cofactors such as metabolites and metals, all of which coalesce and function synchronously within the cell. Metalloenzymes allow for such complex chemical processes, as they catalyze a myriad of biochemical reactions both efficiently and selectively, where the metal cofactor provides additional functionality to promote reactivity not readily achieved in their absence. While the past 60 years have yielded considerable insight on how enzymes catalyze these reactions, a need to engineer and develop artificial metalloenzymes has been driven not only by industrial and therapeutic needs, but also by innate human curiosity. The design of miniature enzymes, both rationally and through serendipity, using both organic and inorganic building blocks has been explored by many scientists over the years and significant progress has been made. Herein, recent developments over the past 5 years in areas that have not been recently reviewed are summarized, and prospects for future research in these areas are addressed.
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Affiliation(s)
- Zechariah Thompson
- Evans Laboratory of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA
| | - James Allan Cowan
- Evans Laboratory of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA
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Ma M, Wang Y, Gao N, Liu X, Sun Y, Ren J, Qu X. A Near-Infrared-Controllable Artificial Metalloprotease Used for Degrading Amyloid-β Monomers and Aggregates. Chemistry 2019; 25:11852-11858. [PMID: 31361361 DOI: 10.1002/chem.201902828] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 07/22/2019] [Indexed: 12/28/2022]
Abstract
Proteolysis of amyloid-β (Aβ) is a promising approach against Alzheimer's disease. However, it is not feasible to employ natural hydrolases directly because of their cumbersome preparation and purification, poor stability, and hazardous immunogenicity. Therefore, artificial enzymes have been developed as potential alternatives to natural hydrolases. Since specific cleavage sites of Aβ are usually embedded inside the β-sheet structures that restrict access by artificial enzymes, this strongly hinders their efficiency for practical applications. Herein, we construct a NIR (near-IR) controllable artificial metalloprotease (MoS2 -Co) using a molybdenum disulfide nanosheet (MoS2 ) and a cobalt complex of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (Codota). Evidenced by detailed experimental and theoretical studies, the NIR-enhanced MoS2 -Co can circumvent the restriction by simultaneously inhibition of β-sheet formation and destroying β-sheet structures of the preformed Aβ aggregates in living cell. Furthermore, our designed MoS2 -Co is an easy to graft Aβ-target agent that prevents misdirected or undesirable hydrolysis reactions, and has been demonstrated to cross the blood brain barrier. This method can be adapted for hydrolysis of other kinds of amyloids.
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Affiliation(s)
- Mengmeng Ma
- Laboratory of Chemical Biology and State Key Laboratory of, Rare Earth Resource Utilization, Changchun Institute of, Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, China.,University of Science and Technology of China, Hefei, Anhui, 230026, P.R. China
| | - Ying Wang
- Laboratory of Chemical Biology and State Key Laboratory of, Rare Earth Resource Utilization, Changchun Institute of, Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, China
| | - Nan Gao
- Laboratory of Chemical Biology and State Key Laboratory of, Rare Earth Resource Utilization, Changchun Institute of, Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, China
| | - Xinping Liu
- Laboratory of Chemical Biology and State Key Laboratory of, Rare Earth Resource Utilization, Changchun Institute of, Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, China.,University of Science and Technology of China, Hefei, Anhui, 230026, P.R. China
| | - Yuhuan Sun
- Laboratory of Chemical Biology and State Key Laboratory of, Rare Earth Resource Utilization, Changchun Institute of, Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, China.,University of Science and Technology of China, Hefei, Anhui, 230026, P.R. China
| | - Jinsong Ren
- Laboratory of Chemical Biology and State Key Laboratory of, Rare Earth Resource Utilization, Changchun Institute of, Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, China
| | - Xiaogang Qu
- Laboratory of Chemical Biology and State Key Laboratory of, Rare Earth Resource Utilization, Changchun Institute of, Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, China.,University of Science and Technology of China, Hefei, Anhui, 230026, P.R. China
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Jayasinghe‐Arachchige VM, Hu Q, Sharma G, Paul TJ, Lundberg M, Quinonero D, Parac‐Vogt TN, Prabhakar R. Hydrolysis of chemically distinct sites of human serum albumin by polyoxometalate: A hybrid QM/MM (ONIOM) study. J Comput Chem 2018; 40:51-61. [DOI: 10.1002/jcc.25528] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 06/22/2018] [Accepted: 06/23/2018] [Indexed: 12/28/2022]
Affiliation(s)
| | - Qiaoyu Hu
- Department of Chemistry University of Miami Coral Gables Florida 33146
| | - Gaurav Sharma
- Department of Chemistry University of Miami Coral Gables Florida 33146
| | - Thomas J. Paul
- Department of Chemistry University of Miami Coral Gables Florida 33146
| | - Marcus Lundberg
- Department of Chemistry ‐ Ångström Laboratory Uppsala University 751 21, Uppsala Sweden
| | - David Quinonero
- Department of Chemistry Universitat de les Illes Balears Palma de Mallorca Spain
| | | | - Rajeev Prabhakar
- Department of Chemistry University of Miami Coral Gables Florida 33146
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8
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Zhang T, Yang H, Yang Z, Tan S, Jin J, Liu S, Zhang J. Sulfonated Compounds Bind with Prostatic Acid Phosphatase (PAP 248-286) to Inhibit the Formation of Amyloid Fibrils. ChemistryOpen 2018; 7:447-456. [PMID: 29928568 PMCID: PMC5997223 DOI: 10.1002/open.201800041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Indexed: 12/13/2022] Open
Abstract
The peptide segment of prostatic acid phosphatase (PAP248-286) aggregates to form SEVI (semen-derived enhancer of virus infection) amyloid fibrils. These are characteristic seminal amyloids that have the ability to promote the effect of HIV infection. In this paper, we explore the binding of sulfonated compounds with PAP248-286 through an in silico study. Three derivatives of suramin, NF110, NF279, and NF340, are selected. All of these sulfonated molecules bind to PAP248-286 and alter the conformation of the peptide, even though they have various structures, sizes, and configurations. The compounds bind with PAP248-286 through multiple interactions, such as hydrogen-bonding interactions, hydrophobic interactions, π-π stacking interactions, and electrostatic interactions. However, NF110, which has an X-shaped configuration, has the highest binding affinity of the three derivatives investigated. We also perform surface plasmon resonance and a Congo red assay to validate the results. The interactions between PAP248-286 and the sulfonated compounds are proposed to depend on the orientations of the sulfonate groups and the specific configurations of the compounds instead of the number of sulfonate groups. NF110 molecules occupy the exposed binding sites of PAP248-286, blocking interactions between the peptides. Therefore, these compounds are important in inhibiting the aggregation of PAP248-286. Herein, we provide useful information to develop new efficient microbicides to antagonize seminal amyloid fibrils and to block HIV transmission.
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Affiliation(s)
- Tingting Zhang
- Guangdong Provincial Key Laboratory of New Drug ScreeningSchool of Pharmaceutical SciencesSouthern Medical UniversityGuangzhou510515P.R. China
| | - Haikui Yang
- Guangdong Provincial Key Laboratory of New Drug ScreeningSchool of Pharmaceutical SciencesSouthern Medical UniversityGuangzhou510515P.R. China
| | - Zichao Yang
- Guangdong Provincial Key Laboratory of New Drug ScreeningSchool of Pharmaceutical SciencesSouthern Medical UniversityGuangzhou510515P.R. China
| | - Suiyi Tan
- Guangdong Provincial Key Laboratory of New Drug ScreeningSchool of Pharmaceutical SciencesSouthern Medical UniversityGuangzhou510515P.R. China
| | - Jiabin Jin
- Guangdong Provincial Key Laboratory of New Drug ScreeningSchool of Pharmaceutical SciencesSouthern Medical UniversityGuangzhou510515P.R. China
| | - Shuwen Liu
- Guangdong Provincial Key Laboratory of New Drug ScreeningSchool of Pharmaceutical SciencesSouthern Medical UniversityGuangzhou510515P.R. China
| | - Jiajie Zhang
- Guangdong Provincial Key Laboratory of New Drug ScreeningSchool of Pharmaceutical SciencesSouthern Medical UniversityGuangzhou510515P.R. China
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9
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Zhang T, Sharma G, Paul TJ, Hoffmann Z, Prabhakar R. Effects of Ligand Environment in Zr(IV) Assisted Peptide Hydrolysis. J Chem Inf Model 2017; 57:1079-1088. [PMID: 28398040 DOI: 10.1021/acs.jcim.6b00781] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this DFT study, activities of 11 different N2O4, N2O3, and NO2 core containing Zr(IV) complexes, 4,13-diaza-18-crown-6 (I'N2O4), 1,4,10-trioxa-7,13-diazacyclopentadecane (I'N2O3), and 2-(2-methoxy)ethanol (I'NO2), respectively, and their analogues in peptide hydrolysis have been investigated. Based on the experimental information, these molecules were created by altering protonation states (singly protonated, doubly protonated, or doubly deprotonated) and number of their ligands. The energetics of the I'N2O4, and I'NO2 and their analogues predicted that both stepwise and concerted mechanisms occurred either with similar barriers, or the latter was more favorable than the former. They also showed that the doubly deprotonated form hydrolyzed the peptide bond with substantially lower barriers than the barriers for other protonation states. For NO2 core possessing complexes, Zr-(NO2)(OHH)(H2O/OH)n for n = 1-3, the hydroxyl group containing molecules were found to be more reactive than their water ligand possessing counterparts. The barriers for these complexes reduced with an increase in the coordination number (6-8) of the Zr(IV) ion. Among all 11 molecules, the NO2 core possessing and two hydroxyl group containing I'DNO2-2H complex was found to be the most reactive complex with a barrier of 28.9 kcal/mol. Furthermore, barriers of 27.5, 28.9, and 32.0 kcal/mol for hydrolysis of Gly-Glu (negative), Gly-Gly (neutral), and Gly-Lys (positive) substrates, respectively, by this complex were in agreement with experiments. The activities of these complexes were explained in terms of basicity of their ligand environment and nucleophilicity of the Zr(IV) center using metal-ligand distances, charge on the metal ion, and the metal-nucleophile distance as parameters. These results provide a deeper understanding of the functioning of these complexes and will help design Zr(IV)-based synthetic metallopeptidases.
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Affiliation(s)
- Tingting Zhang
- Department of Chemistry, University of Miami , Coral Gables, Florida 33146, United States
| | - Gaurav Sharma
- Department of Chemistry, University of Miami , Coral Gables, Florida 33146, United States
| | - Thomas J Paul
- Department of Chemistry, University of Miami , Coral Gables, Florida 33146, United States
| | - Zachary Hoffmann
- Department of Chemistry, University of Miami , Coral Gables, Florida 33146, United States
| | - Rajeev Prabhakar
- Department of Chemistry, University of Miami , Coral Gables, Florida 33146, United States
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10
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Metal assisted peptide bond hydrolysis: Chemistry, biotechnology and toxicological implications. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2016.02.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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11
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Zhou YH, Chen LQ, Tao J, Shen JL, Gong DY, Yun RR, Cheng Y. Effective cleavage of phosphodiester promoted by the zinc(II) and copper(II) inclusion complexes of β-cyclodextrin. J Inorg Biochem 2016; 163:176-184. [DOI: 10.1016/j.jinorgbio.2016.07.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 07/06/2016] [Accepted: 07/13/2016] [Indexed: 12/23/2022]
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Sancho MI, Andujar S, Porasso RD, Enriz RD. Theoretical and Experimental Study of Inclusion Complexes of β-Cyclodextrins with Chalcone and 2′,4′-Dihydroxychalcone. J Phys Chem B 2016; 120:3000-11. [DOI: 10.1021/acs.jpcb.5b11317] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Matias I. Sancho
- Universidad Nacional de San Luis, Facultad de Química,
Bioquímica y Farmacia, IMIBIO-CONICET, Chacabuco 917, 5700, San Luis, Argentina
| | - Sebastian Andujar
- Universidad Nacional de San Luis, Facultad de Química,
Bioquímica y Farmacia, IMIBIO-CONICET, Chacabuco 917, 5700, San Luis, Argentina
| | - Rodolfo D. Porasso
- Instituto
de Matemática Aplicada San Luis (IMASL), CONICET, Facultad
de Ciencias Físico Matemáticas y Naturales, Universidad Nacional de San Luis, Av. Ejército de los Andes 950, 5700, San Luis, Argentina
| | - Ricardo D. Enriz
- Universidad Nacional de San Luis, Facultad de Química,
Bioquímica y Farmacia, IMIBIO-CONICET, Chacabuco 917, 5700, San Luis, Argentina
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Zhang T, Ozbil M, Barman A, Paul TJ, Bora RP, Prabhakar R. Theoretical insights into the functioning of metallopeptidases and their synthetic analogues. Acc Chem Res 2015; 48:192-200. [PMID: 25607542 DOI: 10.1021/ar500301y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
CONSPECTUS: The selective hydrolysis of a peptide or amide bond (-(O═)C-NH-) by a synthetic metallopeptidase is required in a wide range of biological, biotechnological, and industrial applications. In nature, highly specialized enzymes known as proteases and peptidases are used to accomplish this daunting task. Currently, many peptide bond cleaving enzymes and synthetic reagents have been utilized to achieve efficient peptide hydrolysis. However, they possess some serious limitations. To overcome these inadequacies, a variety of metal complexes have been developed that mimic the activities of natural enzymes (metallopeptidases). However, in comparison to metallopeptidases, the hydrolytic reactions facilitated by their existing synthetic analogues are considerably slower and occur with lower catalytic turnover. This could be due to the following reasons: (1) they lack chemical properties of amino acid residues found within enzyme active sites; (2) they contain a higher metal coordination number compared with naturally occurring enzymes; and (3) they do not have access to second coordination shell residues that provide substantial rate enhancements in enzymes. Additionally, the critical structural and mechanistic information required for the development of the next generation of synthetic metallopeptidases cannot be readily obtained through existing experimental techniques. This is because most experimental techniques cannot follow the individual chemical steps in the catalytic cycle due to the fast rate of enzymes. They are also limited by the fact that the diamagnetic d(10) Zn(II) center is silent to electronic, electron spin resonance, and (67)Zn NMR spectroscopies. Therefore, we have employed molecular dynamics (MD), quantum mechanics (QM), and hybrid quantum mechanics/molecular mechanics (QM/MM) techniques to derive this information. In particular, the role of the metal ions, ligands, and microenvironment in the functioning of mono- and binuclear metal center containing enzymes such as insulin degrading enzyme (IDE) and bovine lens leucine aminopeptidase (BILAP), respectively, and their synthetic analogues have been investigated. Our results suggested that in the functioning of IDE, the chemical nature of the peptide bond played a role in the energetics of the reaction and the peptide bond cleavage occurred in the rate-limiting step of the mechanism. In the cocatalytic mechanism used by BILAP, one metal center polarized the scissile peptide bond through the formation of a bond between the metal and the carbonyl group of the substrate, while the second metal center delivered the hydroxyl nucleophile. The Zn(N3) [Zn(His, His, His)] core of matrix metalloproteinase was better than the Zn(N2O) [Zn(His, His, Glu)] core of IDE for peptide hydrolysis. Due to the synergistic interaction between the two metal centers, the binuclear metal center containing Pd2(μ-OH)([18]aneN6)](4+) complex was found to be ∼100 times faster than the mononuclear [Pd(H2O)4](2+) complex. A successful small-molecule synthetic analogue of a mononuclear metallopeptidase must contain a metal with a strong Lewis acidity capable of reducing the pKa of its water ligand to less than 7. Ideally, the metal center should include three ligands with low basicity. The steric effects or strain exerted by the microenvironment could be used to weaken the metal-ligand interactions and increase the activity of the metallopeptidase.
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Affiliation(s)
- Tingting Zhang
- Department
of Chemistry, University of Miami, Coral Gables, Florida 33146, United States
| | - Mehmet Ozbil
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Arghya Barman
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30302-3965, United States
| | - Thomas J. Paul
- Department
of Chemistry, University of Miami, Coral Gables, Florida 33146, United States
| | - Ram Prasad Bora
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-1062, United States
| | - Rajeev Prabhakar
- Department
of Chemistry, University of Miami, Coral Gables, Florida 33146, United States
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