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Schmitz B, Frieg B, Homeyer N, Jessen G, Gohlke H. Extracting binding energies and binding modes from biomolecular simulations of fragment binding to endothiapepsin. Arch Pharm (Weinheim) 2024; 357:e2300612. [PMID: 38319801 DOI: 10.1002/ardp.202300612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/18/2023] [Accepted: 01/10/2024] [Indexed: 02/08/2024]
Abstract
Fragment-based drug discovery (FBDD) aims to discover a set of small binding fragments that may be subsequently linked together. Therefore, in-depth knowledge of the individual fragments' structural and energetic binding properties is essential. In addition to experimental techniques, the direct simulation of fragment binding by molecular dynamics (MD) simulations became popular to characterize fragment binding. However, former studies showed that long simulation times and high computational demands per fragment are needed, which limits applicability in FBDD. Here, we performed short, unbiased MD simulations of direct fragment binding to endothiapepsin, a well-characterized model system of pepsin-like aspartic proteases. To evaluate the strengths and limitations of short MD simulations for the structural and energetic characterization of fragment binding, we predicted the fragments' absolute free energies and binding poses based on the direct simulations of fragment binding and compared the predictions to experimental data. The predicted absolute free energies are in fair agreement with the experiment. Combining the MD data with binding mode predictions from molecular docking approaches helped to correctly identify the most promising fragments for further chemical optimization. Importantly, all computations and predictions were done within 5 days, suggesting that MD simulations may become a viable tool in FBDD projects.
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Affiliation(s)
- Birte Schmitz
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Benedikt Frieg
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- John von Neumann Institute for Computing (NIC), Jülich Supercomputing Centre (JSC), and Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany
| | - Nadine Homeyer
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Gisela Jessen
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- John von Neumann Institute for Computing (NIC), Jülich Supercomputing Centre (JSC), and Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany
- Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich, Jülich, Germany
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2
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Gomes BF, Senger MR, Moreira-Filho JT, de Vasconcellos FJ, Dantas RF, Owens R, Andrade CH, Neves BJ, Silva-Junior FP. Discovery of new Schistosoma mansoni aspartyl protease inhibitors by structure-based virtual screening. Mem Inst Oswaldo Cruz 2023; 118:e230031. [PMID: 37672425 PMCID: PMC10481938 DOI: 10.1590/0074-02760230031] [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: 02/15/2023] [Accepted: 08/01/2023] [Indexed: 09/08/2023] Open
Abstract
BACKGROUND Schistosomiasis is a neglected tropical disease caused by trematodes of the genus Schistosoma, with a limited treatment, mainly based on the use of praziquantel (PZQ). Currently, several aspartic proteases genes have already been identified within the genome of Schistosoma species. At least one enzyme encoded from this gene family (SmAP), named SmCD1, has been validated for the development of schistosomicidal drugs, since it has a key role in haemoglobin digestion by worms. OBJECTIVE In this work, we integrated a structure-based virtual screening campaign, enzymatic assays and adult worms ex vivo experiments aiming to discover the first classes of SmCD1 inhibitors. METHODS Initially, the 3D-structures of SmCD1, SmCD2 and SmCD3 were generated using homology modelling approach. Using these models, we prioritised 50 compounds from 20,000 compounds from ChemBridge database for further testing in adult worm aqueous extract (AWAE) and recombinant SmCD1 using enzymatic assays. FINDINGS Seven compounds were confirmed as hits and among them, two compounds representing new chemical scaffolds, named 5 and 19, had IC50 values against SmCD1 close to 100 μM while presenting binding efficiency indexes comparable to or even higher than pepstatin, a classical tight-binding peptide inhibitor of aspartyl proteases. Upon activity comparison against mammalian enzymes, compound 50 was selective and the most potent against the AWAE aspartic protease activity (IC50 = 77.7 μM). Combination of computational and experimental results indicate that compound 50 is a selective inhibitor of SmCD2. Compounds 5, 19 and 50 tested at low concentrations (10 uM) were neither cytotoxic against WSS-1 cells (48 h) nor could kill adult worms ex-vivo, although compounds 5 and 50 presented a slight decrease on female worms motility on late incubations times (48 or 72 h). MAIN CONCLUSION Overall, the inhibitors identified in this work represent promising hits for further hit-to-lead optimisation.
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Affiliation(s)
- Bárbara Figueira Gomes
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica Experimental e Computacional de Fármacos, Rio de Janeiro, RJ, Brasil
| | - Mario Roberto Senger
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica Experimental e Computacional de Fármacos, Rio de Janeiro, RJ, Brasil
| | - José Teófilo Moreira-Filho
- Universidade Federal de Goiás, Faculdade de Farmácia, Laboratório de Planejamento de Fármacos e Modelagem Molecular, Goiânia, GO, Brasil
| | - Fabio Jorge de Vasconcellos
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica Experimental e Computacional de Fármacos, Rio de Janeiro, RJ, Brasil
| | - Rafael Ferreira Dantas
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica Experimental e Computacional de Fármacos, Rio de Janeiro, RJ, Brasil
| | - Raymond Owens
- University of Oxford and Rosalind Franklin Institute, Oxfordshire, UK
| | - Carolina Horta Andrade
- Universidade Federal de Goiás, Faculdade de Farmácia, Laboratório de Planejamento de Fármacos e Modelagem Molecular, Goiânia, GO, Brasil
| | - Bruno Junior Neves
- Universidade Federal de Goiás, Faculdade de Farmácia, Laboratório de Quimioinformática, Goiânia, GO, Brasil
| | - Floriano Paes Silva-Junior
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica Experimental e Computacional de Fármacos, Rio de Janeiro, RJ, Brasil
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Havranek B, Islam SM. An in silico approach for identification of novel inhibitors as potential therapeutics targeting COVID-19 main protease. J Biomol Struct Dyn 2021; 39:4304-4315. [PMID: 32544024 PMCID: PMC7309303 DOI: 10.1080/07391102.2020.1776158] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 05/25/2020] [Indexed: 01/08/2023]
Abstract
Respiratory disease caused by a novel coronavirus, COVID-19, has been labeled a pandemic by the World Health Organization. Very little is known about the infection mechanism for this virus. More importantly, there are no drugs or vaccines that can cure or prevent a person from getting COVID-19. In this study, the binding affinity of 2692 protease inhibitor compounds that are known in the protein data bank, are calculated against the main protease of the novel coronavirus with docking and molecular dynamics (MD). Both the docking and MD methods predict the macrocyclic tissue factor-factor VIIa (PubChem ID: 118098670) inhibitor to bind strongly with the main protease with a binding affinity of -10.6 and -10.0 kcal/mol, respectively. The TF-FVIIa inhibitors are known to prevent the coagulation of blood and have antiviral activity as shown in the case of SARS coronavirus. Two more inhibitors, phenyltriazolinones (PubChem ID: 104161460) and allosteric HCV NS5B polymerase thumb pocket 2 (PubChem ID: 163632044) have shown antiviral activity and also have high affinity towards the main protease of COVID-19. Furthermore, these inhibitors interact with the catalytic dyad in the active site of the COVID-19 main protease that is especially important in viral replication. The calculated theoretical dissociation constants of the proposed COVID-19 inhibitors are found to be very similar to the experimental dissociation constant values of similar protease-inhibitor systems.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Brandon Havranek
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, USA
| | - Shahidul M. Islam
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, USA
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4
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Advancements in macromolecular crystallography: from past to present. Emerg Top Life Sci 2021; 5:127-149. [PMID: 33969867 DOI: 10.1042/etls20200316] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 04/09/2021] [Accepted: 04/15/2021] [Indexed: 11/17/2022]
Abstract
Protein Crystallography or Macromolecular Crystallography (MX) started as a new discipline of science with the pioneering work on the determination of the protein crystal structures by John Kendrew in 1958 and Max Perutz in 1960. The incredible achievements in MX are attributed to the development of advanced tools, methodologies, and automation in every aspect of the structure determination process, which have reduced the time required for solving protein structures from years to a few days, as evident from the tens of thousands of crystal structures of macromolecules available in PDB. The advent of brilliant synchrotron sources, fast detectors, and novel sample delivery methods has shifted the paradigm from static structures to understanding the dynamic picture of macromolecules; further propelled by X-ray Free Electron Lasers (XFELs) that explore the femtosecond regime. The revival of the Laue diffraction has also enabled the understanding of macromolecules through time-resolved crystallography. In this review, we present some of the astonishing method-related and technological advancements that have contributed to the progress of MX. Even with the rapid evolution of several methods for structure determination, the developments in MX will keep this technique relevant and it will continue to play a pivotal role in gaining unprecedented atomic-level details as well as revealing the dynamics of biological macromolecules. With many exciting developments awaiting in the upcoming years, MX has the potential to contribute significantly to the growth of modern biology by unraveling the mechanisms of complex biological processes as well as impacting the area of drug designing.
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5
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Kemp MT, Lewandowski EM, Chen Y. Low barrier hydrogen bonds in protein structure and function. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2021; 1869:140557. [PMID: 33148530 PMCID: PMC7736181 DOI: 10.1016/j.bbapap.2020.140557] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/17/2020] [Accepted: 10/22/2020] [Indexed: 01/05/2023]
Abstract
Low-barrier hydrogen bonds (LBHBs) are a special type of short hydrogen bond (HB) that is characterized by the equal sharing of a hydrogen atom. The existence and catalytic role of LBHBs in proteins has been intensely contested. Advancements in X-ray and neutron diffraction methods has revealed delocalized hydrogen atoms involved in potential LBHBs in a number of proteins, while also demonstrating that short HBs are not necessarily LBHBs. More importantly, a series of experiments on ketosteroid isomerase (KSI) have suggested that LBHBs are significantly stronger than standard HBs in the protein microenvironment in terms of enthalpy, but not free energy. The discrepancy between the enthalpy and free energy of LBHBs offers clues to the challenges, and potential solutions, of the LBHB debate, where the unique strength of LBHBs plays a special role in the kinetic processes of enzyme function and structure, together with other molecular forces in a pre-organized environment.
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Affiliation(s)
- M Trent Kemp
- Department of Molecular Medicine, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd, MDC 3522, Tampa, Florida 33612, United States
| | - Eric M Lewandowski
- Department of Molecular Medicine, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd, MDC 3522, Tampa, Florida 33612, United States
| | - Yu Chen
- Department of Molecular Medicine, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd, MDC 3522, Tampa, Florida 33612, United States.
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6
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Gu CX, Zhang BL, Bai WW, Liu J, Zhou W, Ling ZQ, Lu Y, Xu L, Wan YJ. Characterization of the endothiapepsin-like protein in the entomopathogenic fungus Beauveria bassiana and its virulence effect on the silkworm, Bombyx mori. J Invertebr Pathol 2019; 169:107277. [PMID: 31715184 DOI: 10.1016/j.jip.2019.107277] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/06/2019] [Accepted: 11/07/2019] [Indexed: 12/17/2022]
Abstract
Endothiapepsin is an aspartic proteinase that was first isolated from the plant pathogenic fungus Endothia parasitica. In previous studies, we reported on three endothiapepsin-like proteins in the entomopathogenic fungus Beauveria bassiana; the genes were up-regulated in B. bassiana hyper-virulent strain GXsk1011 at early stage infection in the silkworm. However, whether these proteins play a role in pathogenicity or not remains unknown. In this study, we cloned one protein, BbepnL-1 gene (BBA-07766), that has 98% homology with B. bassiana strain Bb2860, and expressed it in the yeast Pichia pastoris to investigate its function. The endothiapepsin-like protein is a secreted proteinase of molecular weight approximately 40 kDa. It has an N-glycosylation site and a mutation in the C-terminal conserved domain- a Thr was mutated to Gly in B. bassiana GXsk1011 and is different than the endothiapepsin of Endothia parasitica. The recombinant endothiapepsin-like protein showed enzyme activity and degraded the protein components of the silkworm cuticle. To further investigate the activity of the endothiapepsin-like protein, we knocked out the gene BbepnL-1 and showed that the loss of BbepnL-1 reduced the virulence in the silkworm. These results demonstrated that the endothiapepsin-like protein of B. bassiana is a virulence factor.
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Affiliation(s)
- Cai-Xia Gu
- Laboratory of Invertebrate Pathology and Applied Microbiology, College of Biotechnology, Southwest University, Chongqing 400716, China
| | - Bao-Ling Zhang
- Laboratory of Invertebrate Pathology and Applied Microbiology, College of Biotechnology, Southwest University, Chongqing 400716, China
| | - Wen-Wen Bai
- Laboratory of Invertebrate Pathology and Applied Microbiology, College of Biotechnology, Southwest University, Chongqing 400716, China
| | - Jing Liu
- Laboratory of Invertebrate Pathology and Applied Microbiology, College of Biotechnology, Southwest University, Chongqing 400716, China
| | - Wei Zhou
- Laboratory of Invertebrate Pathology and Applied Microbiology, College of Biotechnology, Southwest University, Chongqing 400716, China
| | - Zi-Qi Ling
- Laboratory of Invertebrate Pathology and Applied Microbiology, College of Biotechnology, Southwest University, Chongqing 400716, China
| | - Yan Lu
- Laboratory of Invertebrate Pathology and Applied Microbiology, College of Biotechnology, Southwest University, Chongqing 400716, China
| | - Liang Xu
- Laboratory of Invertebrate Pathology and Applied Microbiology, College of Biotechnology, Southwest University, Chongqing 400716, China
| | - Yong-Ji Wan
- Laboratory of Invertebrate Pathology and Applied Microbiology, College of Biotechnology, Southwest University, Chongqing 400716, China.
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7
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Mishra V, Rathore I, Arekar A, Sthanam LK, Xiao H, Kiso Y, Sen S, Patankar S, Gustchina A, Hidaka K, Wlodawer A, Yada RY, Bhaumik P. Deciphering the mechanism of potent peptidomimetic inhibitors targeting plasmepsins - biochemical and structural insights. FEBS J 2018; 285:3077-3096. [PMID: 29943906 DOI: 10.1111/febs.14598] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 06/10/2018] [Accepted: 06/22/2018] [Indexed: 11/28/2022]
Abstract
Malaria is a deadly disease killing worldwide hundreds of thousands people each year and the responsible parasite has acquired resistance to the available drug combinations. The four vacuolar plasmepsins (PMs) in Plasmodium falciparum involved in hemoglobin (Hb) catabolism represent promising targets to combat drug resistance. High antimalarial activities can be achieved by developing a single drug that would simultaneously target all the vacuolar PMs. We have demonstrated for the first time the use of soluble recombinant plasmepsin II (PMII) for structure-guided drug discovery with KNI inhibitors. Compounds used in this study (KNI-10742, 10743, 10395, 10333, and 10343) exhibit nanomolar inhibition against PMII and are also effective in blocking the activities of PMI and PMIV with the low nanomolar Ki values. The high-resolution crystal structures of PMII-KNI inhibitor complexes reveal interesting features modulating their differential potency. Important individual characteristics of the inhibitors and their importance for potency have been established. The alkylamino analog, KNI-10743, shows intrinsic flexibility at the P2 position that potentiates its interactions with Asp132, Leu133, and Ser134. The phenylacetyl tripeptides, KNI-10333 and KNI-10343, accommodate different ρ-substituents at the P3 phenylacetyl ring that determine the orientation of the ring, thus creating novel hydrogen-bonding contacts. KNI-10743 and KNI-10333 possess significant antimalarial activity, block Hb degradation inside the food vacuole, and show no cytotoxicity on human cells; thus, they can be considered as promising candidates for further optimization. Based on our structural data, novel KNI derivatives with improved antimalarial activity could be designed for potential clinical use. DATABASE: Structural data are available in the PDB under the accession numbers 5YIE, 5YIB, 5YID, 5YIC, and 5YIA.
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Affiliation(s)
- Vandana Mishra
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Ishan Rathore
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Anagha Arekar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Lakshmi Kavitha Sthanam
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Huogen Xiao
- Department of Molecular and Cellular Biology, University of Guelph, ON, Canada
| | - Yoshiaki Kiso
- Laboratory of Peptide Sciences, Nagahama Institute of Bio-Science and Technology, Japan
| | - Shamik Sen
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Swati Patankar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Alla Gustchina
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Koushi Hidaka
- Division of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Japan
| | - Alexander Wlodawer
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Rickey Y Yada
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada
| | - Prasenjit Bhaumik
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
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8
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Crisma M, Formaggio F, Alemán C, Torras J, Ramakrishnan C, Kalmankar N, Balaram P, Toniolo C. The fully‐extended conformation in peptides and proteins. Pept Sci (Hoboken) 2018. [DOI: 10.1002/bip.23100] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Marco Crisma
- Institute of Biomolecular Chemistry, Padova Unit, CNRPadova35131 Italy
| | - Fernando Formaggio
- Institute of Biomolecular Chemistry, Padova Unit, CNRPadova35131 Italy
- Department of ChemistryUniversity of PadovaPadova35131 Italy
| | - Carlos Alemán
- Departament d'Enginyeria QuímicaEEBE, Universitat Politècnica de CatalunyaBarcelona08019 Spain
- Barcelona Research Center in Multiscale Science and EngineeringUniversitat Politècnica de CatalunyaBarcelona08019 Spain
| | - Joan Torras
- Departament d'Enginyeria QuímicaEEBE, Universitat Politècnica de CatalunyaBarcelona08019 Spain
- Barcelona Research Center in Multiscale Science and EngineeringUniversitat Politècnica de CatalunyaBarcelona08019 Spain
| | | | - Neha Kalmankar
- National Centre for Biological Sciences (TIFR), GKVK CampusBangalore560065 India
| | | | - Claudio Toniolo
- Institute of Biomolecular Chemistry, Padova Unit, CNRPadova35131 Italy
- Department of ChemistryUniversity of PadovaPadova35131 Italy
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Lin J, Pozharski E, Wilson MA. Short Carboxylic Acid-Carboxylate Hydrogen Bonds Can Have Fully Localized Protons. Biochemistry 2017; 56:391-402. [PMID: 27989121 PMCID: PMC5805389 DOI: 10.1021/acs.biochem.6b00906] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Short hydrogen bonds (H-bonds) have been proposed to play key functional roles in several proteins. The location of the proton in short H-bonds is of central importance, as proton delocalization is a defining feature of low-barrier hydrogen bonds (LBHBs). Experimentally determining proton location in H-bonds is challenging. Here, bond length analysis of atomic (1.15-0.98 Å) resolution X-ray crystal structures of the human protein DJ-1 and its bacterial homologue, YajL, was used to determine the protonation states of H-bonded carboxylic acids. DJ-1 contains a buried, dimer-spanning 2.49 Å H-bond between Glu15 and Asp24 that satisfies standard donor-acceptor distance criteria for a LBHB. Bond length analysis indicates that the proton is localized on Asp24, excluding a LBHB at this location. However, similar analysis of the Escherichia coli homologue YajL shows both residues may be protonated at the H-bonded oxygen atoms, potentially consistent with a LBHB. A Protein Data Bank-wide screen identifies candidate carboxylic acid H-bonds in approximately 14% of proteins, which are typically short [⟨dO-O⟩ = 2.542(2) Å]. Chemically similar H-bonds between hydroxylated residues (Ser/Thr/Tyr) and carboxylates show a trend of lengthening O-O distance with increasing H-bond donor pKa. This trend suggests that conventional electronic effects provide an adequate explanation for short, charge-assisted carboxylic acid-carboxylate H-bonds in proteins, without the need to invoke LBHBs in general. This study demonstrates that bond length analysis of atomic resolution X-ray crystal structures provides a useful experimental test of certain candidate LBHBs.
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Affiliation(s)
- Jiusheng Lin
- Department of Biochemistry and the Redox Biology Center, University of Nebraska, Lincoln, NE, 68588
| | - Edwin Pozharski
- Department of Biochemistry and Molecular Biology, Center for Biomolecular Therapeutics, University of Maryland School of Medicine, Baltimore, MD, 21201,Institute for Bioscience and Biotechnology Research, Rockville, MD 20850,To whom correspondence can be addressed: Edwin Pozharski: or Mark A. Wilson:
| | - Mark A. Wilson
- Department of Biochemistry and the Redox Biology Center, University of Nebraska, Lincoln, NE, 68588,To whom correspondence can be addressed: Edwin Pozharski: or Mark A. Wilson:
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10
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Sabbah DA, Zhong HA. Modeling the protonation states of β-secretase binding pocket by molecular dynamics simulations and docking studies. J Mol Graph Model 2016; 68:206-215. [DOI: 10.1016/j.jmgm.2016.07.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 07/06/2016] [Accepted: 07/17/2016] [Indexed: 01/12/2023]
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11
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Dostál J, Pecina A, Hrušková-Heidingsfeldová O, Marečková L, Pichová I, Řezáčová P, Lepšík M, Brynda J. Atomic resolution crystal structure of Sapp2p, a secreted aspartic protease from Candida parapsilosis. ACTA ACUST UNITED AC 2015; 71:2494-504. [PMID: 26627656 DOI: 10.1107/s1399004715019392] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/13/2015] [Indexed: 11/10/2022]
Abstract
The virulence of the Candida pathogens is enhanced by the production of secreted aspartic proteases, which therefore represent possible targets for drug design. Here, the crystal structure of the secreted aspartic protease Sapp2p from Candida parapsilosis was determined. Sapp2p was isolated from its natural source and crystallized in complex with pepstatin A, a classical aspartic protease inhibitor. The atomic resolution of 0.83 Å allowed the protonation states of the active-site residues to be inferred. A detailed comparison of the structure of Sapp2p with the structure of Sapp1p, the most abundant C. parapsilosis secreted aspartic protease, was performed. The analysis, which included advanced quantum-chemical interaction-energy calculations, uncovered molecular details that allowed the experimentally observed equipotent inhibition of both isoenzymes by pepstatin A to be rationalized.
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Affiliation(s)
- Jiří Dostál
- Institute of Organic Chemistry and Biochemistry (IOCB), Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic
| | - Adam Pecina
- Institute of Organic Chemistry and Biochemistry (IOCB), Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic
| | - Olga Hrušková-Heidingsfeldová
- Institute of Organic Chemistry and Biochemistry (IOCB), Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic
| | - Lucie Marečková
- Institute of Organic Chemistry and Biochemistry (IOCB), Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic
| | - Iva Pichová
- Institute of Organic Chemistry and Biochemistry (IOCB), Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic
| | - Pavlina Řezáčová
- Institute of Organic Chemistry and Biochemistry (IOCB), Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic
| | - Martin Lepšík
- Institute of Organic Chemistry and Biochemistry (IOCB), Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic
| | - Jiří Brynda
- Institute of Organic Chemistry and Biochemistry (IOCB), Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic
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12
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Microbial aspartic proteases: current and potential applications in industry. Appl Microbiol Biotechnol 2014; 98:8853-68. [PMID: 25269600 DOI: 10.1007/s00253-014-6035-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 08/15/2014] [Accepted: 08/16/2014] [Indexed: 01/18/2023]
Abstract
Aspartic proteases are a relatively small group of proteolytic enzymes that are active in acidic environments and are found across all forms of life. Certain microorganisms secrete such proteases as virulence agents and/or in order to break down proteins thereby liberating assimilable sources of nitrogen. Some of the earlier applications of these proteolytic enzymes are found in the manufacturing of cheese where they are used as milk-clotting agents. Over the last decade, they have received tremendous research interest because of their involvement in human diseases. Furthermore, there has also been a growing interest on these enzymes for their applications in several other industries. Recent research suggests in particular that they could be used in the wine industry to prevent the formation of protein haze while preserving the wines' organoleptic properties. In this mini-review, the properties and mechanisms of action of aspartic proteases are summarized. Thereafter, a brief overview of the industrial applications of this specific class of proteases is provided. The use of aspartic proteases as alternatives to clarifying agents in various beverage industries is mentioned, and the potential applications in the wine industry are thoroughly discussed.
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13
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Li Z, Hao A, Li X. β-Cyclodextrin supramolecular organogels induced by different carboxylic acids that exhibit diverse morphologies. J Mol Liq 2014. [DOI: 10.1016/j.molliq.2014.03.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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14
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Guo J, Cooper JB, Wood SP. The structure of endothiapepsin complexed with a Phe-Tyr reduced-bond inhibitor at 1.35 Å resolution. Acta Crystallogr F Struct Biol Commun 2014; 70:30-3. [PMID: 24419612 PMCID: PMC3943106 DOI: 10.1107/s2053230x13032974] [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: 11/11/2013] [Accepted: 12/05/2013] [Indexed: 11/11/2022] Open
Abstract
Endothiapepsin is a typical member of the aspartic proteinase family. The catalytic mechanism of this family is attributed to two conserved catalytic aspartate residues, which coordinate the hydrolysis of a peptide bond. An oligopeptide inhibitor (IC50 = 0.62 µM) based on a reduced-bond transition-state inhibitor of mucorpepsin was co-crystallized with endothiapepsin and the crystal structure of the enzyme-inhibitor complex was determined at 1.35 Å resolution. A total of 12 hydrogen bonds between the inhibitor and the active-site residues were identified. The resulting structure demonstrates a number of novel subsite interactions in the active-site cleft.
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Affiliation(s)
- J. Guo
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - J. B. Cooper
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - S. P. Wood
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
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15
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Zhang GQ, Zhang QP, Sun Y, Tian YP, Zhou ND. Purification of a Novel Pepsin Inhibitor from Coriolus versicolor and its Biochemical Properties. J Food Sci 2012; 77:C293-7. [DOI: 10.1111/j.1750-3841.2011.02581.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Köster H, Craan T, Brass S, Herhaus C, Zentgraf M, Neumann L, Heine A, Klebe G. A small nonrule of 3 compatible fragment library provides high hit rate of endothiapepsin crystal structures with various fragment chemotypes. J Med Chem 2011; 54:7784-96. [PMID: 21972967 DOI: 10.1021/jm200642w] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Druglike molecules are defined by Lipinski's rule of 5, to characterize fragment thresholds, they have been reduced from 5 to 3 (Astex's rule of 3). They are applied to assemble fragment libraries, and providers use them to select fragments for commercial offer. We question whether these rules are too stringent to compose fragment libraries with candidates exhibiting sufficient room for chemical subsequent growing and merging modifications as appropriate functional groups for chemical transformations are required. Usually these groups exhibit properties as hydrogen bond donors/acceptors and provide entry points for optimization chemistry. We therefore designed a fragment library (364 entries) without strictly applying the rule of 3. For initial screening for endothiapepsin binding, we performed a biochemical cleavage assay of a fluorogenic substrate at 1 mM. "Hits" were defined to inhibit the enzyme by at least 40%. Fifty-five hits were suggested and subsequently soaked into endothiapepsin crystals. Eleven crystal structures could be determined covering fragments with diverse binding modes: (i) direct binding to the catalytic dyad aspartates, (ii) water-mediated binding to the aspartates, (iii) no direct interaction with the dyad. They occupy different specificity pockets. Only 4 of the 11 fragments are consistent with the rule of 3. Restriction to this rule would have limited the fragment hits to a strongly reduced variety of chemotypes.
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Affiliation(s)
- Helene Köster
- Department of Pharmaceutical Chemistry, Philipps University Marburg, Marbacher Weg 6, 35032 Marburg, Germany
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17
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Abstract
The binding states of the substrates and the environment have significant influence on protein motion. We present the analysis of such motion derived from anisotropic atomic displacement parameters (ADPs) in a set of atomic resolution protein structures. Local structural motion caused by ligand binding as well as functional loops showing cooperative patterns of motion could be inferred. The results are in line with proposed protonation states, hydrogen bonding patterns and the location of distinctly flexible regions: we could locate the mobile active site loop in a virus integrase, distinguish the subdomains in RNAse A and hydroxynitrile lyase, and reconstruct the molecular architecture in a xylanase. We demonstrate that the ADP-based motion analysis provides information at high level of detail and that the structural changes needed for substrate attachment or release may be derived from single X-ray structures.
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Affiliation(s)
- Andrea Schmidt
- European Molecular Biology Laboratory, Hamburg Unit, c/o DESY, Notkestrasse 85, D-22607 Hamburg, Germany.
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18
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Pícha J, Buděšínský M, Fiedler P, Sanda M, Jiráček J. Synthesis of α-carboxyphosphinopeptides derived from norleucine. Amino Acids 2010; 39:1265-80. [PMID: 20349321 DOI: 10.1007/s00726-010-0561-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Accepted: 03/09/2010] [Indexed: 11/25/2022]
Abstract
In the present study, we describe in detail the synthesis of a relatively rare class of phosphorus compounds, α-carboxyphosphinopeptides. We prepared several norleucine-derived α-carboxyphosphinic pseudopeptides of the general formula Nle-Ψ[PO(OH)]-Gly. These compounds could have important applications as transition state-mimicking inhibitors for methionine or leucine aminopeptidases or other enzymes. For the preparation of the key α-carboxyphosphinate protected precursors, we investigated, compared and improved two different synthetic methods described in literature: the Arbuzov reaction of a silylated N-protected phosphinic acid with a bromoacetate ester and the nucleophilic addition of a mixed O-methyl S-phenyl N-protected phosphonic acid or a methyl N-protected phosphonochloridate with tert-butyl lithioacetate. We also prepared two N-Fmoc protected synthons, Fmoc-Nle-Ψ[PO(OH)]-Gly-COOH and Fmoc-Nle-Ψ[PO(OAd)]-Gly-COOH, and demonstrated that these precursors are suitable building blocks for the solid-phase synthesis of α-carboxyphosphinopeptides.
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Affiliation(s)
- Jan Pícha
- Institute of Organic Chemistry and Biochemistry, v. v. i., Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10, Prague 6, Czech Republic
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19
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Witt AC, Lakshminarasimhan M, Remington BC, Hasim S, Pozharski E, Wilson MA. Cysteine pKa depression by a protonated glutamic acid in human DJ-1. Biochemistry 2008; 47:7430-40. [PMID: 18570440 DOI: 10.1021/bi800282d] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human DJ-1, a disease-associated protein that protects cells from oxidative stress, contains an oxidation-sensitive cysteine (C106) that is essential for its cytoprotective activity. The origin of C106 reactivity is obscure, due in part to the absence of an experimentally determined p K a value for this residue. We have used atomic-resolution X-ray crystallography and UV spectroscopy to show that C106 has a depressed p K a of 5.4 +/- 0.1 and that the C106 thiolate accepts a hydrogen bond from a protonated glutamic acid side chain (E18). X-ray crystal structures and cysteine p K a analysis of several site-directed substitutions at residue 18 demonstrate that the protonated carboxylic acid side chain of E18 is required for the maximal stabilization of the C106 thiolate. A nearby arginine residue (R48) participates in a guanidinium stacking interaction with R28 from the other monomer in the DJ-1 dimer and elevates the p K a of C106 by binding an anion that electrostatically suppresses thiol ionization. Our results show that the ionizable residues (E18, R48, and R28) surrounding C106 affect its p K a in a way that is contrary to expectations based on the typical ionization behavior of glutamic acid and arginine. Lastly, a search of the Protein Data Bank (PDB) produces several candidate hydrogen-bonded aspartic/glutamic acid-cysteine interactions, which we propose are particularly common in the DJ-1 superfamily.
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Affiliation(s)
- Anna C Witt
- Department of Biochemistry and Redox Biology Center, The University of Nebraska, Lincoln, Nebraska 68588-0664, USA
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20
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Coates L, Tuan HF, Tomanicek S, Kovalevsky A, Mustyakimov M, Erskine P, Cooper J. The catalytic mechanism of an aspartic proteinase explored with neutron and X-ray diffraction. J Am Chem Soc 2008; 130:7235-7. [PMID: 18479128 DOI: 10.1021/ja801269x] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hydrogen atoms play key roles in enzyme mechanism, but as this study shows, even high-quality X-ray data to a resolution of 1 A cannot directly visualize them. Neutron diffraction, however, can locate deuterium atoms even at resolutions around 2 A. Both neutron and X-ray diffraction data have been used to investigate the transition state of the aspartic proteinase endothiapepsin. The different techniques reveal a different part of the story, revealing the clearest picture yet of the catalytic mechanism by which the enzyme operates. Room temperature neutron and X-ray diffraction data were used in a newly developed joint refinement software package to visualize deuterium atoms within the active site of the enzyme when a gem-diol transition state analogue inhibitor is bound at the active site. These data were also used to estimate their individual occupancy, while analysis of the differences between the bond lengths of the catalytic aspartates was performed using atomic resolution X-ray data. The two methods are in agreement on the protonation state of the active site with a transition state analogue inhibitor bound confirming the catalytic mechanism at which the enzyme operates.
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Affiliation(s)
- Leighton Coates
- Spallation Neutron Source, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, USA
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21
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Tuan HF, Erskine P, Langan P, Cooper J, Coates L. Preliminary neutron and ultrahigh-resolution X-ray diffraction studies of the aspartic proteinase endothiapepsin cocrystallized with a gem-diol inhibitor. Acta Crystallogr Sect F Struct Biol Cryst Commun 2007; 63:1080-3. [PMID: 18084100 PMCID: PMC2344097 DOI: 10.1107/s1744309107061283] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Accepted: 11/20/2007] [Indexed: 11/10/2022]
Abstract
Endothiapepsin has been cocrystallized with the gem-diol inhibitor PD-135,040 in a low solvent-content (39%) unit cell, which is unprecedented for this enzyme-inhibitor complex and enables ultrahigh-resolution (1.0 A) X-ray diffraction data to be collected. This atomic resolution X-ray data set will be used to deduce the protonation states of the catalytic aspartate residues. A room-temperature neutron data set has also been collected for joint refinement with a room-temperature X-ray data set in order to locate the H/D atoms at the active site.
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Affiliation(s)
- Han-Fang Tuan
- Spallation Neutron Source, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831, USA
| | - Peter Erskine
- Laboratory for Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Department of Medicine (Hampstead Campus), Rowland Hill Street, London NW3 2PF, England
| | - Paul Langan
- Bioscience Division, Mailstop M888, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
- Department of Chemistry, University of Toledo, Toledo, OH 53606, USA
| | - Jon Cooper
- Laboratory for Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Department of Medicine (Hampstead Campus), Rowland Hill Street, London NW3 2PF, England
| | - Leighton Coates
- Spallation Neutron Source, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831, USA
- Department of Chemistry, University of Toledo, Toledo, OH 53606, USA
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22
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Cosgrove S, Rogers L, Hewage CM, Malthouse JPG. NMR Study of the Inhibition of Pepsin by Glyoxal Inhibitors: Mechanism of Tetrahedral Intermediate Stabilization by the Aspartyl Proteases. Biochemistry 2007; 46:11205-15. [PMID: 17824620 DOI: 10.1021/bi701000k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Z-Ala-Ala-Phe-glyoxal (where Z is benzyloxycarbonyl) has been shown to be a competitive inhibitor of pepsin with a Ki = 89 +/- 24 nM at pH 2.0 and 25 degrees C. Both the ketone carbon (R13COCHO) and the aldehyde carbon (RCO13CHO) of the glyoxal group of Z-Ala-Ala-Phe-glyoxal have been 13C-enriched. Using 13C NMR, it has been shown that when the inhibitor is bound to pepsin, the glyoxal keto and aldehyde carbons give signals at 98.8 and 90.9 ppm, respectively. This demonstrates that pepsin binds and preferentially stabilizes the fully hydrated form of the glyoxal inhibitor Z-Ala-Ala-Phe-glyoxal. From 13C NMR pH studies with glyoxal inhibitor, we obtain no evidence for its hemiketal or hemiacetal hydroxyl groups ionizing to give oxyanions. We conclude that if an oxyanion is formed its pKa must be >8.0. Using 1H NMR, we observe four hydrogen bonds in free pepsin and in pepsin/Z-Ala-Ala-Phe-glyoxal complexes. In the pepsin/pepstatin complex an additional hydrogen bond is formed. We examine the effect of pH on hydrogen bond formation, but we do not find any evidence for low-barrier hydrogen bond formation in the inhibitor complexes. We conclude that the primary role of hydrogen bonding to catalytic tetrahedral intermediates in the aspartyl proteases is to correctly orientate the tetrahedral intermediate for catalysis.
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Affiliation(s)
- Sonya Cosgrove
- UCD School of Biomolecular and Biomedical Science, Centre for Synthesis and Chemical Biology, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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23
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Bjelic S, Aqvist J. Catalysis and Linear Free Energy Relationships in Aspartic Proteases. Biochemistry 2006; 45:7709-23. [PMID: 16784222 DOI: 10.1021/bi060131y] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aspartic proteases are receiving considerable attention as potential drug targets in several serious diseases, such as AIDS, malaria, and Alzheimer's disease. These enzymes cleave polypeptide chains, often between specific amino acid residues, but despite the common reaction mechanism, they exhibit large structural differences. Here, the catalytic mechanism of aspartic proteases plasmepsin II, cathepsin D, and HIV-1 protease is examined by computer simulations utilizing the empirical valence bond approach in combination with molecular dynamics and free energy perturbation calculations. Free energy profiles are established for four different substrates, each six amino acids long and containing hydrophobic side chains in the P1 and P1' positions. Our simulations reproduce the catalytic effect of these enzymes, which accelerate the reaction rate by a factor of approximately 10(10) compared to that of the corresponding uncatalyzed reaction in water. The calculations elucidate the origin of the catalytic effect and allow a rationalization of the fact that, despite large structural differences between plasmepsin II/cathepsin D and HIV-1 protease, the magnitude of their rate enhancement is very similar. Amino acid residues surrounding the active site together with structurally conserved water molecules are found to play an important role in catalysis, mainly through dipolar (electrostatic) stabilization. A linear free energy relationship for the reactions in the different enzymes is established that also demonstrates the reduced reorganization energy in the enzymes compared to that in the uncatalyzed water reaction.
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Affiliation(s)
- Sinisa Bjelic
- Department of Cell and Molecular Biology, Uppsala University Biomedical Center, Box 596, SE-751 24 Uppsala, Sweden
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24
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Coates L, Erskine PT, Mall S, Gill R, Wood SP, Myles DAA, Cooper JB. X-ray, neutron and NMR studies of the catalytic mechanism of aspartic proteinases. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2006; 35:559-66. [PMID: 16673078 DOI: 10.1007/s00249-006-0065-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2006] [Revised: 03/24/2006] [Accepted: 04/04/2006] [Indexed: 11/24/2022]
Abstract
Current proposals for the catalytic mechanism of aspartic proteinases are largely based on X-ray structures of bound oligopeptide inhibitors possessing non-hydrolysable analogues of the scissile peptide bond. Until recent years, the positions of protons on the catalytic aspartates and the ligand in these complexes had not been determined with certainty due to the inadequate resolution of these analyses. There has been much interest in locating the catalytic protons at the active site of aspartic proteinases since this has major implications for detailed understanding of the mechanism of action and the design of improved transition state mimics for therapeutic applications. In this review we discuss the results of studies which have shed light on the locations of protons at the catalytic centre. The first direct determination of the proton positions stemmed from neutron diffraction data collected from crystals of the fungal aspartic proteinase endothiapepsin bound to a transition state analogue (H261). The neutron structure of the complex at a resolution of 2.1 A provided evidence that Asp 215 is protonated and that Asp 32 is the negatively charged residue in the transition state complex. Atomic resolution X-ray studies of inhibitor complexes have corroborated this finding. A similar study of the native enzyme established that it, unexpectedly, has a dipeptide bound at the catalytic site which is consistent with classical reports of inhibition by short peptides and the ability of pepsins to catalyse transpeptidation reactions. Studies by NMR have confirmed the findings of low-barrier and single-well hydrogen bonds in the complexes with transition state analogues.
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Affiliation(s)
- Leighton Coates
- School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton, SO16 7PX, England
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25
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Drug-Target Binding Investigated by Quantum Mechanical/Molecular Mechanical (QM/MM) Methods. ACTA ACUST UNITED AC 2006. [DOI: 10.1007/3-540-35284-8_17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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26
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Vidossich P, Carloni P. Binding of Phosphinate and Phosphonate Inhibitors to Aspartic Proteases: A First-Principles Study. J Phys Chem B 2005; 110:1437-42. [PMID: 16471695 DOI: 10.1021/jp0544639] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phosphinate and phosphonate derivatives are potent inhibitors of aspartic proteases (APs). The affinity for the enzyme might be caused by the presence of low barrier hydrogen bonds between the ligand and the catalytic Asp dyad in the cleavage site. We have used density functional theory calculations along with hybrid quantum mechanics/molecular mechanics Car-Parrinello molecular dynamics simulations to investigate the hydrogen-bonding pattern at the binding site of the complexes of human immunodeficiency virus type-1 AP and the eukaryotic endothiapepsin and penicillopepsin. Our calculations are in fair agreement with the NMR data available for endothiapepsin (Coates et al. J. Mol. Biol. 2002, 318, 1405-1415) and show that the most stable active site configuration is the diprotonated, negatively charged form. In the viral complex both protons are located at the catalytic Asp dyad, while in the eukaryotic complexes the proton shared by the closest oxygen atoms is located at the phosphinic/phosphonic group.
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Affiliation(s)
- Pietro Vidossich
- International School for Advanced Studies and INFM-Democritos Modeling Center for Research in Atomistic Simulation, via Beirut 2-4 34014 Trieste, Italy
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27
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Rajamani R, Reynolds CH. Modeling the protonation states of the catalytic aspartates in beta-secretase. J Med Chem 2004; 47:5159-66. [PMID: 15456259 DOI: 10.1021/jm049817j] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Beta-secretase (BACE) is a critical enzyme in the production of beta-amyloid, a protein that has been implicated as a potential cause of Alzheimer's disease (AD). There are two aspartic acid residues (Asp 32 and Asp 228) present in the catalytic region of BACE that can adopt multiple protonation states. The protonation state and precise location of the protons for these two residues, particularly in the presence of an inhibitor, are subjects of great interest since they have a direct bearing on the mechanism of aspartyl proteases and efforts to model beta-secretase. We have carried out full liner-scaling quantum mechanical (QM) calculations that include Poisson-Boltzmann solvation in order to identify the preferred protonation state and proton location in the presence and absence of an inhibitor. These calculations favor the monoprotonated state in the presence of ligand, and di-deprotonated state in the absence of ligand. Further the proton in the monoprotonated state is located on the inner oxygen of Asp 228. These results have implications for the catalytic mechanism of BACE and related aspartyl proteases. They also provide a reference state for the protein in structure-based modeling studies of this therapeutically important target.
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Affiliation(s)
- Ramkumar Rajamani
- Johnson & Johnson Pharmaceutical R&D, Welsh and McKean Roads, PO Box 776, Spring House, PA 19477, USA
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28
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Fujimoto Z, Fujii Y, Kaneko S, Kobayashi H, Mizuno H. Crystal structure of aspartic proteinase from Irpex lacteus in complex with inhibitor pepstatin. J Mol Biol 2004; 341:1227-35. [PMID: 15321718 DOI: 10.1016/j.jmb.2004.06.049] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2004] [Revised: 06/04/2004] [Accepted: 06/15/2004] [Indexed: 11/21/2022]
Abstract
The crystal structure of Irpex lacteus aspartic proteinase (ILAP) in complex with pepstatin (a six amino acid residue peptide-like inhibitor) was determined at 1.3A resolution. ILAP is a pepsin-like enzyme, widely distributed in nature, with high milk-clotting activity relative to proteolytic activity. The overall structure was in good topological agreement with pepsin and other aspartic proteases. The structure and interaction pattern around the catalytic site were conserved, in agreement with the other aspartic proteinase/inhibitor complex structures reported previously. The high-resolution data also supported the transition state model, as proposed previously for the catalytic mechanism of aspartic proteinase. Unlike the other aspartic proteinases, ILAP was found to require hydrophobic residues either in the P(1) or P(1') site, and also in the P(4) and/or P(3) site(s) for secondary interactions. The inhibitor complex structure also revealed the substrate binding mechanism of ILAP at the P(3) and P(4) site of the substrate, where the inserted loop built up the unique hydrophobic pocket at the P(4) site.
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Affiliation(s)
- Zui Fujimoto
- Department of Biochemistry, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan.
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29
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Brynda J, Rezacova P, Fabry M, Horejsi M, Stouracova R, Sedlacek J, Soucek M, Hradilek M, Lepsik M, Konvalinka J. A phenylnorstatine inhibitor binding to HIV-1 protease: geometry, protonation, and subsite-pocket interactions analyzed at atomic resolution. J Med Chem 2004; 47:2030-6. [PMID: 15056001 DOI: 10.1021/jm031105q] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The X-ray structure of a complex of HIV-1 protease (PR) with a phenylnorstatine inhibitor Z-Pns-Phe-Glu-Glu-NH(2) has been determined at 1.03 A, the highest resolution so far reported for any HIV PR complex. The inhibitor shows subnanomolar K(i) values for both the wild-type PR and the variant representing one of the most common mutations linked to resistance development. The structure comprising the phenylnorstatine moiety of (2R,3S)-chirality displays a unique pattern of hydrogen bonding to the two catalytic aspartate residues. This high resolution makes it possible to assess the donor and acceptor relations of this hydrogen bonding and to indicate a proton shared by the two catalytic residues. A structural mechanism for the unimpaired inhibition of the protease Val82Ala mutant is also suggested, based on energy calculations and analyses.
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Affiliation(s)
- Jiri Brynda
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16637 Prague 6, Czech Republic.
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30
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Tolstoy PM, Schah-Mohammedi P, Smirnov SN, Golubev NS, Denisov GS, Limbach HH. Characterization of Fluxional Hydrogen-Bonded Complexes of Acetic Acid and Acetate by NMR: Geometries and Isotope and Solvent Effects. J Am Chem Soc 2004; 126:5621-34. [PMID: 15113234 DOI: 10.1021/ja039280j] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
1H, (2)H, and (13)C NMR spectra of enriched CH(3)(13)COOH acid without and in the presence of tetra-n-butylammonium acetate have been measured around 110 K using a liquefied Freon mixture CDF(3)/CDF(2)Cl as a solvent, as a function of the deuterium fraction in the mobile proton sites. For comparison, spectra were also taken of the adduct CH(3)(13)COOH.SbCl(5) 1 and of CH(2)Cl(13)COOH under similar conditions, as well as of CH(3)(13)COOH and CH(3)(13)COO(-) dissolved in H(2)O and D(2)O at low and high pH at 298 K. The low temperatures employed allowed us to detect several well-known and novel hydrogen-bonded complexes in the slow hydrogen bond exchange regime and to determine chemical shifts and coupling constants as well as H/D isotope effects on chemical shifts from the fine structure of the corresponding signals. The measurements show that self-association of both carboxylic acids in Freon solution gives rise exclusively to the formation of cyclic dimers 2 and 3 exhibiting a rapid degenerate double proton transfer. For the first time, a two-bond coupling of the type (2)J(CH(3)COOH) between a hydrogen-bonded proton and the carboxylic carbon has been observed, which is slightly smaller than half of the value observed for 1. In addition, the (1)H and (2)H chemical shifts of the HH, HD, and the DD isotopologues of 2 and 3 have been determined as well as the corresponding HH/HD/DD isotope effects on the (13)C chemical shifts. Similar "primary", "vicinal", and "secondary" isotope effects were observed for the novel 2:1 complex "dihydrogen triacetate" 5 between acetic acid and acetate. Another novel species is the 3:1 complex "trihydrogen tetraacetate" 6, which was also characterized by a complex degenerate combined hydrogen bond- and proton-transfer process. For comparison, the results obtained previously for hydrogen diacetate 4 and hydrogen maleate 7 are discussed. Using an improved (1)H chemical shift-hydrogen bond geometry correlation, the chemical shift data are converted into hydrogen bond geometries. They indicate cooperative hydrogen bonds in the cyclic dimers; i.e., widening of a given hydrogen bond by H/D substitution also widens the other coupled hydrogen bond. By contrast, the hydrogen bonds in 5 are anticooperative. The measurements show that ionization shifts the (13)C signal of the carboxyl group to low field when the group is immersed in water, but to high field when it is embedded in a polar aprotic environment. This finding allows us to understand the unusual ionization shift of aspartate groups in the HIV-pepstatin complex observed by Smith, R.; Brereton, I. M.; Chai, R. Y.; Kent, S. B. H. Nature Struct. Biol. 1996, 3, 946. It is demonstrated that the Freon solvents used in this study are better environments for model studies of amino acid interactions than aqueous or protic environments. Finally, a novel correlation of the hydrogen bond geometries with the H/D isotope effects on the (13)C chemical shifts of carboxylic acid groups is proposed, which allows one to estimate the hydrogen bond geometries and protonation states of these groups. It is shown that absence of such an isotope effect is not only compatible with an isolated carboxylate group but also with the presence of a short and strong hydrogen bond.
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Affiliation(s)
- Peter M Tolstoy
- Institut für Chemie, Freie Universität Berlin, Takustrasse 3, D-14195 Berlin, Germany
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31
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Erskine PT, Coates L, Mall S, Gill RS, Wood SP, Myles DAA, Cooper JB. Atomic resolution analysis of the catalytic site of an aspartic proteinase and an unexpected mode of binding by short peptides. Protein Sci 2003; 12:1741-9. [PMID: 12876323 PMCID: PMC2323960 DOI: 10.1110/ps.0305203] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The X-ray structures of native endothiapepsin and a complex with a hydroxyethylene transition state analog inhibitor (H261) have been determined at atomic resolution. Unrestrained refinement of the carboxyl groups of the enzyme by using the atomic resolution data indicates that both catalytic aspartates in the native enzyme share a single negative charge equally; that is, in the crystal, one half of the active sites have Asp 32 ionized and the other half have Asp 215 ionized. The electron density map of the native enzyme refined at 0.9 A resolution demonstrates that there is a short peptide (probably Ser-Thr) bound noncovalently in the active site cleft. The N-terminal nitrogen of the dipeptide interacts with the aspartate diad of the enzyme by hydrogen bonds involving the carboxyl of Asp 215 and the catalytic water molecule. This is consistent with classical findings that the aspartic proteinases can be inhibited weakly by short peptides and that these enzymes can catalyze transpeptidation reactions. The dipeptide may originate from autolysis of the N-terminal Ser-Thr sequence of the enzyme during crystallization.
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Affiliation(s)
- Peter T Erskine
- Division of Biochemistry and Molecular Biology, School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK
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32
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Kamitori S, Ohtaki A, Ino H, Takeuchi M. Crystal structures of Aspergillus oryzae aspartic proteinase and its complex with an inhibitor pepstatin at 1.9A resolution. J Mol Biol 2003; 326:1503-11. [PMID: 12595261 DOI: 10.1016/s0022-2836(03)00078-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The X-ray structures of Aspergillus oryzae aspartic proteinase (AOAP) and its complex with inhibitor pepstatin have been determined at 1.9A resolution. AOAP was crystallized in an orthorhombic system with the space group P2(1)2(1)2(1) and cell dimensions of a=49.4A, b=79.4A, and c=93.6A. By the soaking of pepstatin, crystals are transformed into a monoclinic system with the space group C2 and cell dimensions of a=106.8A, b=38.6A, c=78.7A, and beta=120.3 degrees. The structures of AOAP and AOAP/pepstatin complex were refined to an R-factor of 0.177 (R(free)=0.213) and of 0.185 (0.221), respectively. AOAP has a crescent-shaped structure with two lobes (N-lobe and C-lobe) and the deep active site cleft is constructed between them. At the center of the active site cleft, two Asp residues (Asp33 and Asp214) form the active dyad with a hydrogen bonding solvent molecule between them. Pepstatin binds to the active site cleft via hydrogen bonds and hydrophobic interactions with the enzyme. The structures of AOAP and AOAP/pepstatin complex including interactions between the enzyme and pepstatin are very similar to those of other structure-solved aspartic proteinases and their complexes with pepstatin. Generally, aspartic proteinases cleave a peptide bond between hydrophobic amino acid residues, but AOAP can also recognize the Lys/Arg residue as well as hydrophobic amino acid residues, leading to the activation of trypsinogen and chymotrypsinogen. The X-ray structure of AOAP/pepstatin complex and preliminary modeling show two possible sites of recognition for the positively charged groups of Lys/Arg residues around the active site of AOAP.
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Affiliation(s)
- Shigehiro Kamitori
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.
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33
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Toulokhonova L, Metzler WJ, Witmer MR, Copeland RA, Marcinkeviciene J. Kinetic studies on beta-site amyloid precursor protein-cleaving enzyme (BACE). Confirmation of an iso mechanism. J Biol Chem 2003; 278:4582-9. [PMID: 12458195 DOI: 10.1074/jbc.m210471200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The steady-state kinetic mechanism of beta-amyloid precursor protein-cleaving enzyme (BACE)-catalyzed proteolytic cleavage was evaluated using product and statine- (Stat(V)) or hydroxyethylene-containing (OM99-2) peptide inhibition data, solvent kinetic isotope effects, and proton NMR spectroscopy. The noncompetitive inhibition pattern observed for both cleavage products, together with the independence of Stat(V) inhibition on substrate concentration, suggests a uni-bi-iso kinetic mechanism. According to this mechanism, the enzyme undergoes multiple conformation changes during the catalytic cycle. If any of these steps are rate-limiting to turnover, an enzyme form preceding the rate-limiting conformational change should accumulate. An insignificant solvent kinetic isotope effect (SKIE) on k(cat)/K(m), a large inverse solvent kinetic isotope effect on k(cat), and the absence of any SKIE on the inhibition onset by Stat(V) during catalysis together indicate that the rate-limiting iso-step occurs after formation of a tetrahedral intermediate. A moderately short and strong hydrogen bond (at delta 13.0 ppm and phi of 0.6) has been observed by NMR spectroscopy in the enzyme-hydroxyethylene peptide (OM99-2) complex that presumably mimics the tetrahedral intermediate of catalysis. Collapse of this intermediate, involving multiple steps and interconversion of enzyme forms, has been suggested to impose a rate limitation, which is manifested in a significant SKIE on k(cat). Multiple enzyme forms and their distribution during catalysis were evaluated by measuring the SKIE on the noncompetitive (mixed) inhibition constants for the C-terminal reaction product. Large, normal SKIE values were observed for these inhibition constants, suggesting that both kinetic and thermodynamic components contribute to the K(ii) and K(is) expressions, as has been suggested for other iso-mechanism featuring enzymes. We propose that a conformational change related to the reprotonation of aspartates during or after the bond-breaking event is the rate-limiting segment in the catalytic reaction of beta-amyloid precursor protein-cleaving enzyme, and ligands binding to other than the ground-state forms of the enzyme might provide inhibitors of greater pharmacological relevance.
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Affiliation(s)
- Larisa Toulokhonova
- Department of Chemical Enzymology, Bristol-Myers Squibb Pharmaceutical Company, Wilmington, Delaware 19880-0400, USA
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