1
|
Ge M, Molt RW, Jenkins HT, Blackburn GM, Jin Y, Antson AA. Octahedral Trifluoromagnesate, an Anomalous Metal Fluoride Species, Stabilizes the Transition State in a Biological Motor. ACS Catal 2021; 11:2769-2773. [PMID: 33717640 PMCID: PMC7944477 DOI: 10.1021/acscatal.0c04500] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 12/26/2020] [Indexed: 01/11/2023]
Abstract
![]()
Isoelectronic metal
fluoride transition state analogue (TSA) complexes,
MgF3– and AlF4–, have proven to be immensely useful in understanding mechanisms
of biological motors utilizing phosphoryl transfer. Here we report
a previously unobserved octahedral TSA complex, MgF3(H2O)−, in a 1.5 Å resolution Zika virus
NS3 helicase crystal structure. 19F NMR provided independent
validation and also the direct observation of conformational tightening
resulting from ssRNA binding in solution. The TSA stabilizes the two
conformations of motif V of the helicase that link ATP hydrolysis
with mechanical work. DFT analysis further validated the MgF3(H2O)− species, indicating the significance
of this TSA for studies of biological motors.
Collapse
Affiliation(s)
- Mengyu Ge
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, YO10 5DD, United Kingdom
| | - Robert W. Molt
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, United States
- ENSCO, Inc., 4849 North Wickham Road, Melbourne, Florida 32940, United States
| | - Huw T. Jenkins
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, YO10 5DD, United Kingdom
| | - G. Michael Blackburn
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Yi Jin
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff, CF10 3AT, United Kingdom
| | - Alfred A. Antson
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, YO10 5DD, United Kingdom
| |
Collapse
|
2
|
Johnson LA, Robertson AJ, Baxter NJ, Trevitt CR, Bisson C, Jin Y, Wood HP, Hounslow AM, Cliff MJ, Blackburn GM, Bowler MW, Waltho JP. van der Waals Contact between Nucleophile and Transferring Phosphorus Is Insufficient To Achieve Enzyme Transition-State Architecture. ACS Catal 2018. [DOI: 10.1021/acscatal.8b01612] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Luke A. Johnson
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Angus J. Robertson
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Nicola J. Baxter
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester M1 7DN, United Kingdom
| | - Clare R. Trevitt
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Claudine Bisson
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Yi Jin
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Henry P. Wood
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Andrea M. Hounslow
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Matthew J. Cliff
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester M1 7DN, United Kingdom
| | - G. Michael Blackburn
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Matthew W. Bowler
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, F-38042 Grenoble, France
| | - Jonathan P. Waltho
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester M1 7DN, United Kingdom
| |
Collapse
|
3
|
Wang Q, He Y, Lu R, Wang WM, Yang KW, Fan HM, Jin Y, Blackburn GM. Thermokinetic profile of NDM-1 and its inhibition by small carboxylic acids. Biosci Rep 2018; 38:BSR20180244. [PMID: 29507059 PMCID: PMC5897741 DOI: 10.1042/bsr20180244] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 02/16/2018] [Accepted: 03/03/2018] [Indexed: 01/09/2023] Open
Abstract
The New Delhi metallo-β-lactamase (NDM-1) is an important clinical target for antimicrobial research, but there are insufficient clinically useful inhibitors and the details of NDM-1 enzyme catalysis remain unclear. The aim of this work is to provide a thermodynamic profile of NDM-1 catalysed hydrolysis of β-lactams using an isothermal titration calorimetry (ITC) approach and to apply this new method to the identification of new low-molecular-weight dicarboxylic acid inhibitors. The results reveal that hydrolysis of penicillin G and imipenem by NDM-1 share the same thermodynamic features with a significant intrinsic enthalpy change and the release of one proton into solution, while NDM-1 hydrolysis of cefazolin exhibits a different mechanism with a smaller enthalpy change and the release of two protons. The inhibitory constants of four carboxylic acids are found to be in the micromolar range. The compounds pyridine-2,6-dicarboxylic acid and thiazolidine-2,4-dicarboxylic acid show the best inhibitory potency and are confirmed to inhibit NDM-1 using a clinical strain of Escherichia coli The pyridine compound is further shown to restore the susceptibility of this E. coli strain to imipenem, at an inhibitor concentration of 400 μM, while the thiazoline compound also shows a synergistic effect with imipenem. These results provide valuable information to enrich current understanding on the catalytic mechanism of NDM-1 and to aid the future optimisation of β-lactamase inhibitors based on these scaffolds to tackle the problem of antibiotic resistance.
Collapse
Affiliation(s)
- Qian Wang
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, 1 Xue Fu Avenue, Xi'an 710127, P.R. China
| | - Yuan He
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, 1 Xue Fu Avenue, Xi'an 710127, P.R. China
| | - Rui Lu
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, 1 Xue Fu Avenue, Xi'an 710127, P.R. China
| | - Wen-Ming Wang
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, 1 Xue Fu Avenue, Xi'an 710127, P.R. China
| | - Ke-Wu Yang
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, 1 Xue Fu Avenue, Xi'an 710127, P.R. China
| | - Hai Ming Fan
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, 1 Xue Fu Avenue, Xi'an 710127, P.R. China
| | - Yi Jin
- School of Chemistry, Cardiff University, Cardiff CF10 3AT, U.K
| | - G Michael Blackburn
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K
| |
Collapse
|
4
|
Golovin AV, Smirnov IV, Stepanova AV, Zalevskiy AO, Zlobin AS, Ponomarenko NA, Belogurov AA, Knorre VD, Hurs EN, Chatziefthimiou SD, Wilmanns M, Blackburn GM, Khomutov RM, Gabibov AG. Evolution of catalytic centers of antibodies by virtual screening of broad repertoire of mutants using supercomputer. DOKL BIOCHEM BIOPHYS 2017; 475:245-249. [PMID: 28864894 DOI: 10.1134/s1607672917040019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Indexed: 11/23/2022]
Abstract
It is proposed to perform quantum mechanical/molecular dynamics calculations of chemical reactions that are planned to be catalyzed by antibodies and then conduct a virtual screening of the library of potential antibody mutants to select an optimal biocatalyst. We tested the effectiveness of this approach by the example of hydrolysis of organophosphorus toxicant paraoxon using kinetic approaches and X-ray analysis of the antibody biocatalyst designed de novo.
Collapse
Affiliation(s)
- A V Golovin
- Moscow State University, Moscow, 119991, Russia
| | - I V Smirnov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - A V Stepanova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | | | - A S Zlobin
- Moscow State University, Moscow, 119991, Russia
| | - N A Ponomarenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - A A Belogurov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - V D Knorre
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
| | - E N Hurs
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
| | | | - M Wilmanns
- Hamburg Unit, European Molecular Biology Laboratory, Hamburg, Germany
| | - G M Blackburn
- Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, UK
| | - R M Khomutov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
| | - A G Gabibov
- Moscow State University, Moscow, 119991, Russia.,Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| |
Collapse
|
5
|
Jin Y, Molt RW, Pellegrini E, Cliff MJ, Bowler MW, Richards NGJ, Blackburn GM, Waltho JP. Assessing the Influence of Mutation on GTPase Transition States by Using X-ray Crystallography, 19 F NMR, and DFT Approaches. Angew Chem Int Ed Engl 2017; 56:9732-9735. [PMID: 28498638 PMCID: PMC5575484 DOI: 10.1002/anie.201703074] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Indexed: 11/08/2022]
Abstract
We report X-ray crystallographic and 19 F NMR studies of the G-protein RhoA complexed with MgF3- , GDP, and RhoGAP, which has the mutation Arg85'Ala. When combined with DFT calculations, these data permit the identification of changes in transition state (TS) properties. The X-ray data show how Tyr34 maintains solvent exclusion and the core H-bond network in the active site by relocating to replace the missing Arg85' sidechain. The 19 F NMR data show deshielding effects that indicate the main function of Arg85' is electronic polarization of the transferring phosphoryl group, primarily mediated by H-bonding to O3G and thence to PG . DFT calculations identify electron-density redistribution and pinpoint why the TS for guanosine 5'-triphosphate (GTP) hydrolysis is higher in energy when RhoA is complexed with RhoGAPArg85'Ala relative to wild-type (WT) RhoGAP. This study demonstrates that 19 F NMR measurements, in combination with X-ray crystallography and DFT calculations, can reliably dissect the response of small GTPases to site-specific modifications.
Collapse
Affiliation(s)
- Yi Jin
- Department of Molecular Biology and Biotechnology, Krebs Institute, University of Sheffield, Sheffield, S10 2TN, UK.,School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK
| | - Robert W Molt
- School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK.,Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,ENSCO, Inc., Melbourne, FL, 32940, USA
| | - Erika Pellegrini
- Structural Biology Group, ESRF-The European Synchrotron, CS40220, 38043, Grenoble, Cedex 9, France
| | - Matthew J Cliff
- Manchester Institute of Biotechnology, Manchester, M1 7DN, UK
| | - Matthew W Bowler
- Structural Biology Group, ESRF-The European Synchrotron, CS40220, 38043, Grenoble, Cedex 9, France.,European Molecular Biology Laboratory, Grenoble Outstation CS90181, 38042, Grenoble, Cedex 9, France
| | | | - G Michael Blackburn
- Department of Molecular Biology and Biotechnology, Krebs Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | - Jonathan P Waltho
- Department of Molecular Biology and Biotechnology, Krebs Institute, University of Sheffield, Sheffield, S10 2TN, UK.,Manchester Institute of Biotechnology, Manchester, M1 7DN, UK
| |
Collapse
|
6
|
Jin Y, Molt RW, Pellegrini E, Cliff MJ, Bowler MW, Richards NGJ, Blackburn GM, Waltho JP. Assessing the Influence of Mutation on GTPase Transition States by Using X‐ray Crystallography,
19
F NMR, and DFT Approaches. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201703074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yi Jin
- Department of Molecular Biology and BiotechnologyKrebs InstituteUniversity of Sheffield Sheffield S10 2TN UK
- School of ChemistryCardiff University Cardiff CF10 3AT UK
| | - Robert W. Molt
- School of ChemistryCardiff University Cardiff CF10 3AT UK
- Department of Biochemistry and Molecular BiologyIndiana University School of Medicine Indianapolis IN 46202 USA
- ENSCO, Inc. Melbourne FL 32940 USA
| | - Erika Pellegrini
- Structural Biology GroupESRF-The European Synchrotron, CS40220 38043 Grenoble, Cedex 9 France
| | | | - Matthew W. Bowler
- Structural Biology GroupESRF-The European Synchrotron, CS40220 38043 Grenoble, Cedex 9 France
- European Molecular Biology Laboratory, Grenoble Outstation CS90181 38042 Grenoble, Cedex 9 France
| | | | - G. Michael Blackburn
- Department of Molecular Biology and BiotechnologyKrebs InstituteUniversity of Sheffield Sheffield S10 2TN UK
| | - Jonathan P. Waltho
- Department of Molecular Biology and BiotechnologyKrebs InstituteUniversity of Sheffield Sheffield S10 2TN UK
- Manchester Institute of Biotechnology Manchester M1 7DN UK
| |
Collapse
|
7
|
Blackburn GM, Cherfils J, Moss GP, Richards NGJ, Waltho JP, Williams NH, Wittinghofer A. How to name atoms in phosphates, polyphosphates, their derivatives and mimics, and transition state analogues for enzyme-catalysed phosphoryl transfer reactions (IUPAC Recommendations 2016). PURE APPL CHEM 2017. [DOI: 10.1515/pac-2016-0202] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractProcedures are proposed for the naming of individual atoms, P, O, F, N, and S in phosphate esters, amidates, thiophosphates, polyphosphates, their mimics, and analogues of transition states for enzyme-catalyzed phosphoryl transfer reactions. Their purpose is to enable scientists in very different fields, e.g. biochemistry, biophysics, chemistry, computational chemistry, crystallography, and molecular biology, to share standard protocols for the labelling of individual atoms in complex molecules. This will facilitate clear and unambiguous descriptions of structural results, as well as scientific intercommunication concerning them. At the present time, perusal of the Protein Data Bank (PDB) and other sources shows that there is a limited degree of commonality in nomenclature, but a large measure of irregularity in more complex structures. The recommendations described here adhere to established practice as closely as possible, in particular to IUPAC and IUBMB recommendations and to “best practice” in the PDB, especially to its atom labelling of amino acids, and particularly to Cahn-Ingold-Prelog rules for stereochemical nomenclature. They are designed to work in complex enzyme sites for binding phosphates but also to have utility for non-enzymatic systems. Above all, the recommendations are designed to be easy to comprehend and user-friendly.
Collapse
Affiliation(s)
- G. Michael Blackburn
- 1Department of Molecular Biology, Krebs Institute, University of Sheffield, S10 2TN, UK
| | - Jacqueline Cherfils
- 2Laboratoire de Biologie et Pharmacologie Appliquée, CNRS – École Normale Supérieure Paris-Saclay, Cachan, France. http://orcid.org/0000-0002-8966-3067
| | - Gerard P. Moss
- 3Queen Mary University of London, School of Biological and Chemical Sciences, London E1 4NS, UK
| | - Nigel G. J. Richards
- 4Department of Chemistry, Indiana University Purdue University Indianapolis, IL 46202, USA; and School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK
| | | | | | - Alfred Wittinghofer
- 7Group for Structural Biology, Max-Planck-Institut für Molekulare Physiologie, 44227 Dortmund, Deutschland
| |
Collapse
|
8
|
Jin Y, Richards NG, Waltho JP, Blackburn GM. Metal Fluorides as Analogues for Studies on Phosphoryl Transfer Enzymes. Angew Chem Int Ed Engl 2017; 56:4110-4128. [PMID: 27862756 DOI: 10.1002/anie.201606474] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Indexed: 12/27/2022]
Abstract
The 1994 structure of a transition-state analogue with AlF4- and GDP complexed to G1α, a small G protein, heralded a new field of research into the structure and mechanism of enzymes that manipulate the transfer of phosphoryl (PO3- ) groups. The number of enzyme structures in the PDB containing metal fluorides (MFx ) as ligands that imitate either a phosphoryl or a phosphate group was 357 at the end of 2016. They fall into three distinct geometrical classes: 1) Tetrahedral complexes based on BeF3- that mimic ground-state phosphates; 2) octahedral complexes, primarily based on AlF4- , which mimic "in-line" anionic transition states for phosphoryl transfer; and 3) trigonal bipyramidal complexes, represented by MgF3- and putative AlF30 moieties, which mimic the geometry of the transition state. The interpretation of these structures provides a deeper mechanistic understanding into the behavior and manipulation of phosphate monoesters in molecular biology. This Review provides a comprehensive overview of these structures, their uses, and their computational development.
Collapse
Affiliation(s)
- Yi Jin
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | | | | | - G Michael Blackburn
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK
| |
Collapse
|
9
|
Affiliation(s)
- Yi Jin
- Department of Chemistry; University of York; York YO10 5DD Großbritannien
| | - Nigel G. Richards
- School of Chemistry; Cardiff University; Cardiff CF10 3AT Großbritannien
| | | | - G. Michael Blackburn
- Department of Molecular Biology and Biotechnology; University of Sheffield; Sheffield S10 2TN Großbritannien
| |
Collapse
|
10
|
Smirnov IV, Golovin AV, Chatziefthimiou SD, Stepanova AV, Peng Y, Zolotareva OI, Belogurov AA, Kurkova IN, Ponomarenko NA, Wilmanns M, Blackburn GM, Gabibov AG, Lerner RA. Robotic QM/MM-driven maturation of antibody combining sites. Sci Adv 2016; 2:e1501695. [PMID: 27774510 PMCID: PMC5072179 DOI: 10.1126/sciadv.1501695] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 09/19/2016] [Indexed: 06/06/2023]
Abstract
In vitro selection of antibodies from large repertoires of immunoglobulin (Ig) combining sites using combinatorial libraries is a powerful tool, with great potential for generating in vivo scavengers for toxins. However, addition of a maturation function is necessary to enable these selected antibodies to more closely mimic the full mammalian immune response. We approached this goal using quantum mechanics/molecular mechanics (QM/MM) calculations to achieve maturation in silico. We preselected A17, an Ig template, from a naïve library for its ability to disarm a toxic pesticide related to organophosphorus nerve agents. Virtual screening of 167,538 robotically generated mutants identified an optimum single point mutation, which experimentally boosted wild-type Ig scavenger performance by 170-fold. We validated the QM/MM predictions via kinetic analysis and crystal structures of mutant apo-A17 and covalently modified Ig, thereby identifying the displacement of one water molecule by an arginine as delivering this catalysis.
Collapse
Affiliation(s)
- Ivan V. Smirnov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ulitsa Miklukho‐Maklaya 16/10, 117997 Moscow V-437, Russian Federation
| | - Andrey V. Golovin
- Lomonosov Moscow State University, Moscow 119991, Russian Federation
| | - Spyros D. Chatziefthimiou
- European Molecular Biology Laboratory, Hamburg Unit, c/o German Synchrotron Research Center, Notkestrasse 85, 22603 Hamburg, Germany
| | - Anastasiya V. Stepanova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ulitsa Miklukho‐Maklaya 16/10, 117997 Moscow V-437, Russian Federation
| | - Yingjie Peng
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road MB-10, La Jolla, CA 92037, USA
| | | | - Alexey A. Belogurov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ulitsa Miklukho‐Maklaya 16/10, 117997 Moscow V-437, Russian Federation
| | - Inna N. Kurkova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ulitsa Miklukho‐Maklaya 16/10, 117997 Moscow V-437, Russian Federation
| | - Natalie A. Ponomarenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ulitsa Miklukho‐Maklaya 16/10, 117997 Moscow V-437, Russian Federation
| | - Matthias Wilmanns
- European Molecular Biology Laboratory, Hamburg Unit, c/o German Synchrotron Research Center, Notkestrasse 85, 22603 Hamburg, Germany
| | - G. Michael Blackburn
- Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, U.K
| | - Alexander G. Gabibov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ulitsa Miklukho‐Maklaya 16/10, 117997 Moscow V-437, Russian Federation
- Lomonosov Moscow State University, Moscow 119991, Russian Federation
| | - Richard A. Lerner
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road MB-10, La Jolla, CA 92037, USA
| |
Collapse
|
11
|
Jin Y, Molt RW, Waltho JP, Richards NGJ, Blackburn GM. (19)F NMR and DFT Analysis Reveal Structural and Electronic Transition State Features for RhoA-Catalyzed GTP Hydrolysis. Angew Chem Int Ed Engl 2016; 55:3318-22. [PMID: 26822702 PMCID: PMC4770445 DOI: 10.1002/anie.201509477] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 01/14/2016] [Indexed: 11/13/2022]
Abstract
Molecular details for RhoA/GAP catalysis of the hydrolysis of GTP to GDP are poorly understood. We use (19)F NMR chemical shifts in the MgF3(-) transition state analogue (TSA) complex as a spectroscopic reporter to indicate electron distribution for the γ-PO3(-) oxygens in the corresponding TS, implying that oxygen coordinated to Mg has the greatest electron density. This was validated by QM calculations giving a picture of the electronic properties of the transition state (TS) for nucleophilic attack of water on the γ-PO3(-) group based on the structure of a RhoA/GAP-GDP-MgF3(-) TSA complex. The TS model displays a network of 20 hydrogen bonds, including the GAP Arg85' side chain, but neither phosphate torsional strain nor general base catalysis is evident. The nucleophilic water occupies a reactive location different from that in multiple ground state complexes, arising from reorientation of the Gln-63 carboxamide by Arg85' to preclude direct hydrogen bonding from water to the target γ-PO3(-) group.
Collapse
Affiliation(s)
- Yi Jin
- Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK
| | - Robert W Molt
- Department of Chemistry and Chemical Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, 46202, USA
| | - Jonathan P Waltho
- Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK.
- Manchester Institute of Biotechnology, Manchester, M1 7DN, UK.
| | - Nigel G J Richards
- Department of Chemistry and Chemical Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, 46202, USA.
- School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK.
| | - G Michael Blackburn
- Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK.
| |
Collapse
|
12
|
Jin Y, Molt RW, Waltho JP, Richards NGJ, Blackburn GM. 19F NMR and DFT Analysis Reveal Structural and Electronic Transition State Features for RhoA-Catalyzed GTP Hydrolysis. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201509477] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yi Jin
- Krebs Institute, Department of Molecular Biology and Biotechnology; University of Sheffield; Sheffield S10 2TN UK
| | - Robert W. Molt
- Department of Chemistry and Chemical Biology; Indiana University Purdue University Indianapolis; Indianapolis IN 46202 USA
| | - Jonathan P. Waltho
- Krebs Institute, Department of Molecular Biology and Biotechnology; University of Sheffield; Sheffield S10 2TN UK
- Manchester Institute of Biotechnology; Manchester M1 7DN UK
| | - Nigel G. J. Richards
- Department of Chemistry and Chemical Biology; Indiana University Purdue University Indianapolis; Indianapolis IN 46202 USA
- School of Chemistry; Cardiff University; Cardiff CF10 3AT UK
| | - G. Michael Blackburn
- Krebs Institute, Department of Molecular Biology and Biotechnology; University of Sheffield; Sheffield S10 2TN UK
| |
Collapse
|
13
|
Terekhov S, Smirnov I, Bobik T, Shamborant O, Zenkova M, Chernolovskaya E, Gladkikh D, Murashev A, Dyachenko I, Palikov V, Palikova Y, Knorre V, Belogurov A, Ponomarenko N, Blackburn GM, Masson P, Gabibov A. A novel expression cassette delivers efficient production of exclusively tetrameric human butyrylcholinesterase with improved pharmacokinetics for protection against organophosphate poisoning. Biochimie 2015; 118:51-9. [DOI: 10.1016/j.biochi.2015.07.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 07/30/2015] [Indexed: 10/23/2022]
|
14
|
Abstract
Early studies on chemical synthesis of biological molecules can be seen to progress to preparation and biological evaluation of phosphonates as analogues of biological phosphates, with emphasis on their isosteric and isopolar character. Work with such mimics progressed into structural studies with a range of nucleotide-utilising enzymes. The arrival of metal fluorides as analogues of the phosphoryl group, PO(3)(-), for transition state (TS) analysis of enzyme reactions stimulated the symbiotic deployment of (19)F NMR and protein crystallography. Characteristics of enzyme transition state analogues are reviewed for a range of reactions. From the available MF(x) species, trifluoroberyllate gives tetrahedral mimics of ground states (GS) in which phosphate is linked to carboxylate and phosphate oxyanions. Tetrafluoroaluminate is widely employed as a TS mimic, but it necessarily imposes octahedral geometry on the assembled complexes, whereas phosphoryl transfer involves trigonal bipyramidal (tbp) geometry. Trifluoromagnesate (MgF(3)(-)) provides the near-ideal solution, delivering tbp geometry and correct anionic charge. Some of the forty reported tbp structures assigned as having AlF(3)(0) cores have been redefined as trifluoromagnesate complexes. Transition state analogues for a range of kinases, mutases, and phosphatases provide a detailed description of mechanism for phosphoryl group transfer, supporting the concept of charge balance in their TS and of concerted-associative pathways for biocatalysis. Above all, superposition of GS and TS structures reveals that in associative phosphoryl transfer, the phosphorus atom migrates through a triangle of three, near-stationary, equatorial oxygens. The extension of these studies to near attack conformers further illuminates enzyme catalysis of phosphoryl transfer.
Collapse
Affiliation(s)
- G M Blackburn
- Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
| | | | | | | |
Collapse
|
15
|
Jin Y, Cliff MJ, Baxter NJ, Dannatt HRW, Hounslow AM, Bowler MW, Blackburn GM, Waltho JP. Charge-Balanced Metal Fluoride Complexes for Protein Kinase A with Adenosine Diphosphate and Substrate Peptide SP20. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201204266] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
16
|
Jin Y, Cliff MJ, Baxter NJ, Dannatt HRW, Hounslow AM, Bowler MW, Blackburn GM, Waltho JP. Charge-balanced metal fluoride complexes for protein kinase A with adenosine diphosphate and substrate peptide SP20. Angew Chem Int Ed Engl 2012; 51:12242-5. [PMID: 23125010 DOI: 10.1002/anie.201204266] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 10/10/2012] [Indexed: 11/10/2022]
Affiliation(s)
- Yi Jin
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Xiaoxia L, Marston JP, Baxter NJ, Hounslow AM, Yufen Z, Blackburn GM, Cliff MJ, Waltho JP. Prioritization of Charge over Geometry in Transition State Analogues of a Dual Specificity Protein Kinase. J Am Chem Soc 2011; 133:3989-94. [DOI: 10.1021/ja1090035] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Liu Xiaoxia
- Krebs Institute and Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
- Fujian Key Laboratory for Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, 361005 Fujian Province, People’s Republic of China
| | - James P. Marston
- Krebs Institute and Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Nicola J. Baxter
- Krebs Institute and Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
- Manchester Interdisciplinary Biocentre, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Andrea M. Hounslow
- Krebs Institute and Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Zhao Yufen
- Fujian Key Laboratory for Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, 361005 Fujian Province, People’s Republic of China
| | - G. Michael Blackburn
- Krebs Institute and Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Matthew J. Cliff
- Krebs Institute and Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Jonathan P. Waltho
- Krebs Institute and Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
- Manchester Interdisciplinary Biocentre, University of Manchester, Manchester M1 7DN, United Kingdom
| |
Collapse
|
18
|
Zeng Z, Luo P, Jiang Y, Liu Y, Tang G, Xu P, Zhao Y, Blackburn GM. Chiral phosphoproline-catalyzed asymmetric Michael addition of ketones to nitroolefins: an experimental and theoretical study. Org Biomol Chem 2011; 9:6973-8. [DOI: 10.1039/c1ob06143g] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
19
|
Cliff MJ, Bowler MW, Varga A, Marston JP, Szabó J, Hounslow AM, Baxter NJ, Blackburn GM, Vas M, Waltho JP. Transition state analogue structures of human phosphoglycerate kinase establish the importance of charge balance in catalysis. J Am Chem Soc 2010; 132:6507-16. [PMID: 20397725 DOI: 10.1021/ja100974t] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Transition state analogue (TSA) complexes formed by phosphoglycerate kinase (PGK) have been used to test the hypothesis that balancing of charge within the transition state dominates enzyme-catalyzed phosphoryl transfer. High-resolution structures of trifluoromagnesate (MgF(3)(-)) and tetrafluoroaluminate (AlF(4)(-)) complexes of PGK have been determined using X-ray crystallography and (19)F-based NMR methods, revealing the nature of the catalytically relevant state of this archetypal metabolic kinase. Importantly, the side chain of K219, which coordinates the alpha-phosphate group in previous ground state structures, is sequestered into coordinating the metal fluoride, thereby creating a charge environment complementary to the transferring phosphoryl group. In line with the dominance of charge balance in transition state organization, the substitution K219A induces a corresponding reduction in charge in the bound aluminum fluoride species, which changes to a trifluoroaluminate (AlF(3)(0)) complex. The AlF(3)(0) moiety retains the octahedral geometry observed within AlF(4)(-) TSA complexes, which endorses the proposal that some of the widely reported trigonal AlF(3)(0) complexes of phosphoryl transfer enzymes may have been misassigned and in reality contain MgF(3)(-).
Collapse
Affiliation(s)
- Matthew J Cliff
- The Krebs Institute & The Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
|
21
|
Marston JP, Cliff MJ, Reed MAC, Blackburn GM, Hounslow AM, Craven CJ, Waltho JP. Structural tightening and interdomain communication in the catalytic cycle of phosphoglycerate kinase. J Mol Biol 2009; 396:345-60. [PMID: 19944703 DOI: 10.1016/j.jmb.2009.11.052] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 11/16/2009] [Accepted: 11/19/2009] [Indexed: 11/25/2022]
Abstract
Changes in amide-NH chemical shift and hydrogen exchange rates as phosphoglycerate kinase progresses through its catalytic cycle have been measured to assess whether they correlate with changes in hydrogen bonding within the protein. Four representative states were compared: the free enzyme, a product complex containing 3-phosphoglyceric acid (3PG), a substrate complex containing ADP and a transition-state analogue (TSA) complex containing a 3PG-AlF(4)(-)-ADP moiety. There are an overall increases in amide protection from hydrogen exchange when the protein binds the substrate and product ligands and an additional increase when the TSA complex is formed. This is consistent with stabilisation of the protein structure by ligand binding. However, there is no correlation between the chemical shift changes and the protection factor changes, indicating that the protection factor changes are not associated with an overall shortening of hydrogen bonds in the protected ground state, but rather can be ascribed to the properties of the high-energy, exchange-competent state. Therefore, an overall structural tightening mechanism is not supported by the data. Instead, we observed that some cooperativity is exhibited in the N-domain, such that within this domain the changes induced upon forming the TSA complex are an intensification of those induced by binding 3PG. Furthermore, chemical shift changes induced by 3PG binding extend through the interdomain region to the C-domain beta-sheet, highlighting a network of hydrogen bonds between the domains that suggests interdomain communication. Interdomain communication is also indicated by amide protection in one domain being significantly altered by binding of substrate to the other, even where no associated change in the structure of the substrate-free domain is indicated by chemical shifts. Hence, the communication between domains is also manifested in the accessibility of higher-energy, exchange-competent states. Overall, the data that are consistent with structural tightening relate to defined regions and are close to the 3PG binding site and in the hinge regions of 3-phosphoglycerate kinase.
Collapse
Affiliation(s)
- James P Marston
- Department of Molecular Biology and Biotechnology, Firth Court, The University of Sheffield, Western Bank, Sheffield, UK
| | | | | | | | | | | | | |
Collapse
|
22
|
Baxter NJ, Hounslow AM, Bowler MW, Williams NH, Blackburn GM, Waltho JP. MgF3− and α-Galactose 1-Phosphate in the Active Site of β-Phosphoglucomutase Form a Transition State Analogue of Phosphoryl Transfer. J Am Chem Soc 2009; 131:16334-5. [DOI: 10.1021/ja905972m] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nicola J. Baxter
- Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom, European Synchrotron Radiation Facility, 6 rue Jules Horowitz, F-38043 Grenoble, France, Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom, and Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Andrea M. Hounslow
- Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom, European Synchrotron Radiation Facility, 6 rue Jules Horowitz, F-38043 Grenoble, France, Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom, and Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Matthew W. Bowler
- Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom, European Synchrotron Radiation Facility, 6 rue Jules Horowitz, F-38043 Grenoble, France, Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom, and Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Nicholas H. Williams
- Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom, European Synchrotron Radiation Facility, 6 rue Jules Horowitz, F-38043 Grenoble, France, Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom, and Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, M1 7DN, United Kingdom
| | - G. Michael Blackburn
- Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom, European Synchrotron Radiation Facility, 6 rue Jules Horowitz, F-38043 Grenoble, France, Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom, and Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Jonathan P. Waltho
- Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom, European Synchrotron Radiation Facility, 6 rue Jules Horowitz, F-38043 Grenoble, France, Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom, and Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, M1 7DN, United Kingdom
| |
Collapse
|
23
|
Hou JB, Zhang H, Guo JN, Liu Y, Xu PX, Zhao YF, Blackburn GM. Chirality at phosphorus in pentacoordinate spirophosphoranes: stereochemistry by X-ray structure and spectroscopic analysis. Org Biomol Chem 2009. [DOI: 10.1039/b909786d] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
24
|
Guranowski A, Wojdyła AM, Pietrowska-Borek M, Bieganowski P, Khurs EN, Cliff MJ, Blackburn GM, Błaziak D, Stec WJ. Fhit proteins can also recognize substrates other than dinucleoside polyphosphates. FEBS Lett 2008; 582:3152-8. [PMID: 18694747 DOI: 10.1016/j.febslet.2008.07.060] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 07/17/2008] [Accepted: 07/31/2008] [Indexed: 11/26/2022]
Abstract
We show here that Fhit proteins, in addition to their function as dinucleoside triphosphate hydrolases, act similarly to adenylylsulfatases and nucleoside phosphoramidases, liberating nucleoside 5'-monophosphates from such natural metabolites as adenosine 5'-phosphosulfate and adenosine 5'-phosphoramidate. Moreover, Fhits recognize synthetic nucleotides, such as adenosine 5'-O-phosphorofluoridate and adenosine 5'-O-(gamma-fluorotriphosphate), and release AMP from them. With respect to the former, Fhits behave like a phosphodiesterase I concomitant with cleavage of the P-F bond. Some kinetic parameters and implications of the novel reactions catalyzed by the human and plant (Arabidopsis thaliana) Fhit proteins are presented.
Collapse
Affiliation(s)
- Andrzej Guranowski
- Department of Biochemistry and Biotechnology, The University of Life Sciences, 60-637 Poznań, Poland.
| | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Hounslow AM, Carran J, Brown RJ, Rejman D, Blackburn GM, Watts DJ. Determination of the microscopic equilibrium dissociation constants for risedronate and its analogues reveals two distinct roles for the nitrogen atom in nitrogen-containing bisphosphonate drugs. J Med Chem 2008; 51:4170-8. [PMID: 18590315 DOI: 10.1021/jm7015792] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Microscopic equilibrium dissociation constants, k as, were determined for four nitrogen-containing bisphosphonates (N-BP): risedronate and its analogues 2-(2-aminophenyl)-1-hydroxyethylidene-1,1-bisphosphonate, NE 11807, and NE 97220. The proportion of each and of analogues 2-(3'-( N-ethyl)pyridinium)-ethylidenebisphosphonate and 2-(3-piperinidyl)-1-hydroxyethylidene-1,1-bisphosphonate, having a positively charged nitrogen and three negative charges on the bisphosphonate group ("carbocation analogue") at pH 7.5, was calculated. When set in order of increasing potency at inhibiting farnesyl diphosphate (FDP) synthase (their intracellular target), the N-BPs are also ranked in order of decreasing mole fraction of carbocation analogue. However, only a weak correlation exists between potency for inhibiting FDP synthase and potency for inhibiting Dictyostelium discoideum growth. It is concluded that, although high potency for inhibiting FDP synthase is favored when the nitrogen atom in a N-BP is uncharged, N-BPs having a positively charged nitrogen can still be potent inhibitors of Dictyostelium growth owing to favorable interaction with a second, unidentified target.
Collapse
Affiliation(s)
- Andrea M Hounslow
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, UK
| | | | | | | | | | | |
Collapse
|
26
|
Jakeman DL, Bernstein B, Hol W, Williams DM, Williamson MP, Blackburn GM. Highly Potent Bisphosphonate Ligands for Phosphoglycerate Kinase and Protein Binding Studies. PHOSPHORUS SULFUR 2008. [DOI: 10.1080/10426509908546299] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- David L. Jakeman
- a Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- b Department of Biochemistry and Biotechnology , University of Sheffield , Sheffield, S10 2TN, UK
- c Department of Biochemistry and Biotechnology , University of Sheffield , Sheffield, S10 2TN, UK
- d Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- e University of Washington, Department of Structural Biology , Seattle, WA 98195, USA
| | - Brad Bernstein
- a Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- b Department of Biochemistry and Biotechnology , University of Sheffield , Sheffield, S10 2TN, UK
- c Department of Biochemistry and Biotechnology , University of Sheffield , Sheffield, S10 2TN, UK
- d Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- e University of Washington, Department of Structural Biology , Seattle, WA 98195, USA
| | - Wim Hol
- a Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- b Department of Biochemistry and Biotechnology , University of Sheffield , Sheffield, S10 2TN, UK
- c Department of Biochemistry and Biotechnology , University of Sheffield , Sheffield, S10 2TN, UK
- d Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- e University of Washington, Department of Structural Biology , Seattle, WA 98195, USA
| | - David M. Williams
- a Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- b Department of Biochemistry and Biotechnology , University of Sheffield , Sheffield, S10 2TN, UK
- c Department of Biochemistry and Biotechnology , University of Sheffield , Sheffield, S10 2TN, UK
- d Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- e University of Washington, Department of Structural Biology , Seattle, WA 98195, USA
| | - Michael P. Williamson
- a Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- b Department of Biochemistry and Biotechnology , University of Sheffield , Sheffield, S10 2TN, UK
- c Department of Biochemistry and Biotechnology , University of Sheffield , Sheffield, S10 2TN, UK
- d Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- e University of Washington, Department of Structural Biology , Seattle, WA 98195, USA
| | - G. Michael Blackburn
- a Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- b Department of Biochemistry and Biotechnology , University of Sheffield , Sheffield, S10 2TN, UK
- c Department of Biochemistry and Biotechnology , University of Sheffield , Sheffield, S10 2TN, UK
- d Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- e University of Washington, Department of Structural Biology , Seattle, WA 98195, USA
| |
Collapse
|
27
|
Affiliation(s)
- Xiaohai Liu
- a Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- b Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- c Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
| | - Xiu-Rong Zhang
- a Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- b Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- c Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
| | - G. Michael Blackburn
- a Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- b Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
- c Krebs Institute, Department of Chemistry , University of Sheffield , Sheffield, S3 7HF, UK
| |
Collapse
|
28
|
Baxter NJ, Blackburn GM, Marston JP, Hounslow AM, Cliff MJ, Bermel W, Williams NH, Hollfelder F, Wemmer DE, Waltho JP. Anionic charge is prioritized over geometry in aluminum and magnesium fluoride transition state analogs of phosphoryl transfer enzymes. J Am Chem Soc 2008; 130:3952-8. [PMID: 18318536 DOI: 10.1021/ja078000n] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phosphoryl transfer reactions are ubiquitous in biology and metal fluoride complexes have played a central role in structural approaches to understanding how they are catalyzed. In particular, numerous structures of AlFx-containing complexes have been reported to be transition state analogs (TSAs). A survey of nucleotide kinases has proposed a correlation between the pH of the crystallization solution and the number of coordinated fluorides in the resulting aluminum fluoride TSA complexes formed. Enzyme ligands crystallized above pH 7.0 were attributed to AlF3, whereas those crystallized at or below pH 7.0 were assigned as AlF4-. We use 19F NMR to show that for beta-phosphoglucomutase from Lactococcus lactis, the pH-switch in fluoride coordination does not derive from an AlF4- moiety converting into AlF3. Instead, AlF4- is progressively replaced by MgF3- as the pH increases. Hence, the enzyme prioritizes anionic charge at the expense of preferred native trigonal geometry over a very broad range of pH. We demonstrate similar behavior for two phosphate transfer enzymes that represent typical biological phosphate transfer catalysts: an amino acid phosphatase, phosphoserine phosphatase from Methanococcus jannaschii and a nucleotide kinase, phosphoglycerate kinase from Geobacillus stearothermophilus. Finally, we establish that at near-physiological ratios of aluminum to magnesium, aluminum can dominate over magnesium in the enzyme-metal fluoride inhibitory TSA complexes, and hence is the more likely origin of some of the physiological effects of fluoride.
Collapse
Affiliation(s)
- Nicola J Baxter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Abstract
Stable analogues of transition states are used as haptens to elicit antibodies that will catalyse the reaction under investigation. The present failure of such antibodies to equal the catalytic efficiency of enzymes has prompted a more detailed analysis of the structure of transition states. Calculations suggest that for many types of reaction, including the Diels-Alder reaction and addition-elimination reactions, interatomic distances in the transition state are longer than those in analogues hitherto used to elicit catalytic antibodies. Three possible solutions are proposed for the design and synthesis of stable analogues that match the longer interatomic distances of transition states: atom substitution, atom insertion and double atom insertion. Some applications of these ideas to specific reactions are described. The concept of expanded transition states is also valuable for associative processes as a way of avoiding product inhibition of the catalytic antibody; this is being explored for a phenylalanine transcarbamylase antibody.
Collapse
Affiliation(s)
- G M Blackburn
- Department of Chemistry, Krebs Institute, Sheffield University, UK
| | | | | | | |
Collapse
|
30
|
|
31
|
Baxter NJ, Olguin LF, Goličnik M, Feng G, Hounslow AM, Bermel W, Blackburn GM, Hollfelder F, Waltho JP, Williams NH. A Trojan horse transition state analogue generated by MgF3- formation in an enzyme active site. Proc Natl Acad Sci U S A 2006; 103:14732-7. [PMID: 16990434 PMCID: PMC1595420 DOI: 10.1073/pnas.0604448103] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Identifying how enzymes stabilize high-energy species along the reaction pathway is central to explaining their enormous rate acceleration. beta-Phosphoglucomutase catalyses the isomerization of beta-glucose-1-phosphate to beta-glucose-6-phosphate and appeared to be unique in its ability to stabilize a high-energy pentacoordinate phosphorane intermediate sufficiently to be directly observable in the enzyme active site. Using (19)F-NMR and kinetic analysis, we report that the complex that forms is not the postulated high-energy reaction intermediate, but a deceptively similar transition state analogue in which MgF(3)(-) mimics the transferring PO(3)(-) moiety. Here we present a detailed characterization of the metal ion-fluoride complex bound to the enzyme active site in solution, which reveals the molecular mechanism for fluoride inhibition of beta-phosphoglucomutase. This NMR methodology has a general application in identifying specific interactions between fluoride complexes and proteins and resolving structural assignments that are indistinguishable by x-ray crystallography.
Collapse
Affiliation(s)
- Nicola J. Baxter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Luis F. Olguin
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | - Marko Goličnik
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | - Guoqiang Feng
- Centre for Chemical Biology, Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom; and
| | - Andrea M. Hounslow
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Wolfgang Bermel
- Bruker BioSpin GmbH, Silberstreifen 4, 76287 Rheinstetten, Germany
| | - G. Michael Blackburn
- Centre for Chemical Biology, Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom; and
| | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
- To whom correspondence may be addressed. E-mail:
, , or
| | - Jonathan P. Waltho
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
- To whom correspondence may be addressed. E-mail:
, , or
| | - Nicholas H. Williams
- Centre for Chemical Biology, Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom; and
- To whom correspondence may be addressed. E-mail:
, , or
| |
Collapse
|
32
|
Russell RJ, Haire LF, Stevens DJ, Collins PJ, Lin YP, Blackburn GM, Hay AJ, Gamblin SJ, Skehel JJ. The structure of H5N1 avian influenza neuraminidase suggests new opportunities for drug design. Nature 2006; 443:45-9. [PMID: 16915235 DOI: 10.1038/nature05114] [Citation(s) in RCA: 612] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Accepted: 07/25/2006] [Indexed: 02/07/2023]
Abstract
The worldwide spread of H5N1 avian influenza has raised concerns that this virus might acquire the ability to pass readily among humans and cause a pandemic. Two anti-influenza drugs currently being used to treat infected patients are oseltamivir (Tamiflu) and zanamivir (Relenza), both of which target the neuraminidase enzyme of the virus. Reports of the emergence of drug resistance make the development of new anti-influenza molecules a priority. Neuraminidases from influenza type A viruses form two genetically distinct groups: group-1 contains the N1 neuraminidase of the H5N1 avian virus and group-2 contains the N2 and N9 enzymes used for the structure-based design of current drugs. Here we show by X-ray crystallography that these two groups are structurally distinct. Group-1 neuraminidases contain a cavity adjacent to their active sites that closes on ligand binding. Our analysis suggests that it may be possible to exploit the size and location of the group-1 cavity to develop new anti-influenza drugs.
Collapse
Affiliation(s)
- Rupert J Russell
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Blackburn GM, Taylor BF, Worrall AF. Synthesis of isomeric 16,17-epoxy-[17-3H)-derivatives of 3-hydroxy and 3-methoxy-oestra-1,3,5(10)-trienes. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580230210] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
34
|
Fisher SZ, Govindasamy L, Boyle N, Agbandje-McKenna M, Silverman DN, Blackburn GM, McKenna R. X-ray crystallographic studies reveal that the incorporation of spacer groups in carbonic anhydrase inhibitors causes alternate binding modes. Acta Crystallogr Sect F Struct Biol Cryst Commun 2006; 62:618-22. [PMID: 16820676 PMCID: PMC2242956 DOI: 10.1107/s1744309106020446] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Accepted: 05/30/2006] [Indexed: 11/10/2022]
Abstract
Human carbonic anhydrases (CAs) are well studied targets for the development of inhibitors for pharmaceutical applications. The crystal structure of human CA II has been determined in complex with two CA inhibitors (CAIs) containing conventional sulfonamide and thiadiazole moieties separated by a -CF2- or -CHNH2- spacer group. The structures presented here reveal that these spacer groups allow novel binding modes for the thiadiazole moiety compared with conventional CAIs.
Collapse
Affiliation(s)
- S. Zoë Fisher
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Lakshmanan Govindasamy
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Nicholas Boyle
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, England
| | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - David N. Silverman
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | | | - Robert McKenna
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Correspondence e-mail:
| |
Collapse
|
35
|
Couture JF, Hauk G, Thompson MJ, Blackburn GM, Trievel RC. Catalytic roles for carbon-oxygen hydrogen bonding in SET domain lysine methyltransferases. J Biol Chem 2006; 281:19280-7. [PMID: 16682405 DOI: 10.1074/jbc.m602257200] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
SET domain enzymes represent a distinct family of protein lysine methyltransferases in eukaryotes. Recent studies have yielded significant insights into the structural basis of substrate recognition and the product specificities of these enzymes. However, the mechanism by which SET domain methyltransferases catalyze the transfer of the methyl group from S-adenosyl-L-methionine to the lysine epsilon-amine has remained unresolved. To elucidate this mechanism, we have determined the structures of the plant SET domain enzyme, pea ribulose-1,5 bisphosphate carboxylase/oxygenase large subunit methyltransferase, bound to S-adenosyl-L-methionine, and its non-reactive analogs Aza-adenosyl-L-methionine and Sinefungin, and characterized the binding of these ligands to a homolog of the enzyme. The structural and biochemical data collectively reveal that S-adenosyl-L-methionine is selectively recognized through carbon-oxygen hydrogen bonds between the cofactor's methyl group and an array of structurally conserved oxygens that comprise the methyl transfer pore in the active site. Furthermore, the structure of the enzyme co-crystallized with the product epsilon-N-trimethyllysine reveals a trigonal array of carbon-oxygen interactions between the epsilon-ammonium methyl groups and the oxygens in the pore. Taken together, these results establish a central role for carbon-oxygen hydrogen bonding in aligning the cofactor's methyl group for transfer to the lysine epsilon-amine and in coordinating the methyl groups after transfer to facilitate multiple rounds of lysine methylation.
Collapse
Affiliation(s)
- Jean-François Couture
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | | | | | | | | |
Collapse
|
36
|
Berrisford JM, Hounslow AM, Akerboom J, Hagen WR, Brouns SJJ, van der Oost J, Murray IA, Michael Blackburn G, Waltho JP, Rice DW, Baker PJ. Evidence Supporting a cis-enediol-based Mechanism for Pyrococcus furiosus Phosphoglucose Isomerase. J Mol Biol 2006; 358:1353-66. [PMID: 16580686 DOI: 10.1016/j.jmb.2006.03.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Revised: 03/06/2006] [Accepted: 03/08/2006] [Indexed: 11/16/2022]
Abstract
The enzymatic aldose ketose isomerisation of glucose and fructose sugars involves the transfer of a hydrogen between their C1 and C2 carbon atoms and, in principle, can proceed through either a direct hydride shift or via a cis-enediol intermediate. Pyrococcus furiosus phosphoglucose isomerase (PfPGI), an archaeal metalloenzyme, which catalyses the interconversion of glucose 6-phosphate and fructose 6-phosphate, has been suggested to operate via a hydride shift mechanism. In contrast, the structurally distinct PGIs of eukaryotic or bacterial origin are thought to catalyse isomerisation via a cis-enediol intermediate. We have shown by NMR that hydrogen exchange between substrate and solvent occurs during the reaction catalysed by PfPGI eliminating the possibility of a hydride-shift-based mechanism. In addition, kinetic measurements on this enzyme have shown that 5-phospho-d-arabinonohydroxamate, a stable analogue of the putative cis-enediol intermediate, is the most potent inhibitor of the enzyme yet discovered. Furthermore, determination and analysis of crystal structures of PfPGI with bound zinc and the substrate F6P, and with a number of competitive inhibitors, and EPR analysis of the coordination of the metal ion within PfPGI, have suggested that a cis-enediol intermediate-based mechanism is used by PfPGI with Glu97 acting as the catalytic base responsible for isomerisation.
Collapse
Affiliation(s)
- John M Berrisford
- The Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Guranowski A, Starzyńska E, Pietrowska-Borek M, Jemielity J, Kowalska J, Darzynkiewicz E, Thompson MJ, Blackburn GM. Methylene analogues of adenosine 5'-tetraphosphate. Their chemical synthesis and recognition by human and plant mononucleoside tetraphosphatases and dinucleoside tetraphosphatases. FEBS J 2006; 273:829-38. [PMID: 16441668 DOI: 10.1111/j.1742-4658.2006.05115.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Adenosine 5'-polyphosphates have been identified in vitro, as products of certain enzymatic reactions, and in vivo. Although the biological role of these compounds is not known, there exist highly specific hydrolases that degrade nucleoside 5'-polyphosphates into the corresponding nucleoside 5'-triphosphates. One approach to understanding the mechanism and function of these enzymes is through the use of specifically designed phosphonate analogues. We synthesized novel nucleotides: alpha,beta-methylene-adenosine 5'-tetraphosphate (pppCH2pA), beta,gamma-methylene-adenosine 5'-tetraphosphate (ppCH2ppA), gamma,delta-methylene-adenosine 5'-tetraphosphate (pCH2pppA), alphabeta,gammadelta-bismethylene-adenosine 5'-tetraphosphate (pCH2ppCH2pA), alphabeta, betagamma-bismethylene-adenosine 5'-tetraphosphate (ppCH2pCH2pA) and betagamma, gammadelta-bis(dichloro)methylene-adenosine 5'-tetraphosphate (pCCl2pCCl2ppA), and tested them as potential substrates and/or inhibitors of three specific nucleoside tetraphosphatases. In addition, we employed these p4A analogues with two asymmetrically and one symmetrically acting dinucleoside tetraphosphatases. Of the six analogues, only pppCH2pA is a substrate of the two nucleoside tetraphosphatases (EC 3.6.1.14), from yellow lupin seeds and human placenta, and also of the yeast exopolyphosphatase (EC 3.6.1.11). Surprisingly, none of the six analogues inhibited these p4A-hydrolysing enzymes. By contrast, the analogues strongly inhibit the (asymmetrical) dinucleoside tetraphosphatases (EC 3.6.1.17) from human and the narrow-leafed lupin. ppCH2ppA and pCH2pppA, inhibited the human enzyme with Ki values of 1.6 and 2.3 nm, respectively, and the lupin enzyme with Ki values of 30 and 34 nm, respectively. They are thereby identified as being the strongest inhibitors ever reported for the (asymmetrical) dinucleoside tetraphosphatases. The three analogues having two halo/methylene bridges are much less potent inhibitors for these enzymes. These novel nucleotides should prove valuable tools for further studies on the cellular functions of mono- and dinucleoside polyphosphates and on the enzymes involved in their metabolism.
Collapse
Affiliation(s)
- Andrzej Guranowski
- Department of Biochemistry and Biotechnology, Agricultural University, Poznań, Poland.
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Glynn SE, Baker PJ, Sedelnikova SE, Davies CL, Eadsforth TC, Levy CW, Rodgers HF, Blackburn GM, Hawkes TR, Viner R, Rice DW. Structure and mechanism of imidazoleglycerol-phosphate dehydratase. Structure 2006; 13:1809-17. [PMID: 16338409 DOI: 10.1016/j.str.2005.08.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 08/18/2005] [Accepted: 08/18/2005] [Indexed: 10/25/2022]
Abstract
The structure of A. thaliana imidazoleglycerol-phosphate dehydratase, an enzyme of histidine biosynthesis and a target for the triazole phosphonate herbicides, has been determined to 3.0 A resolution. The structure is composed of 24 identical subunits arranged in 432 symmetry and shows how the formation of a novel dimanganese cluster is crucial to the assembly of the active 24-mer from an inactive trimeric precursor and to the formation of the active site of the enzyme. Molecular modeling suggests that the substrate is bound to the manganese cluster as an imidazolate moiety that subsequently collapses to yield a diazafulvene intermediate. The mode of imidazolate recognition exploits pseudosymmetry at the active site arising from a combination of the assembly of the particle and the pseudosymmetry present in each subunit as a result of gene duplication. This provides an intriguing example of the role of evolution in the design of Nature's catalysts.
Collapse
Affiliation(s)
- Steven E Glynn
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, United Kingdom
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Spencer J, Read J, Sessions RB, Howell S, Blackburn GM, Gamblin SJ. Antibiotic recognition by binuclear metallo-beta-lactamases revealed by X-ray crystallography. J Am Chem Soc 2006; 127:14439-44. [PMID: 16218639 DOI: 10.1021/ja0536062] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Metallo-beta-lactamases are zinc-dependent enzymes responsible for resistance to beta-lactam antibiotics in a variety of host bacteria, usually Gram-negative species that act as opportunist pathogens. They hydrolyze all classes of beta-lactam antibiotics, including carbapenems, and escape the action of available beta-lactamase inhibitors. Efforts to develop effective inhibitors have been hampered by the lack of structural information regarding how these enzymes recognize and turn over beta-lactam substrates. We report here the crystal structure of the Stenotrophomonas maltophilia L1 enzyme in complex with the hydrolysis product of the 7alpha-methoxyoxacephem, moxalactam. The on-enzyme complex is a 3'-exo-methylene species generated by elimination of the 1-methyltetrazolyl-5-thiolate anion from the 3'-methyl group. Moxalactam binding to L1 involves direct interaction of the two active site zinc ions with the beta-lactam amide and C4 carboxylate, groups that are common to all beta-lactam substrates. The 7beta-[(4-hydroxyphenyl)malonyl]-amino substituent makes limited hydrophobic and hydrogen bonding contacts with the active site groove. The mode of binding provides strong evidence that a water molecule situated between the two metal ions is the most likely nucleophile in the hydrolytic reaction. These data suggest a reaction mechanism for metallo-beta-lactamases in which both metal ions contribute to catalysis by activating the bridging water/hydroxide nucleophile, polarizing the substrate amide bond for attack and stabilizing anionic nitrogen intermediates. The structure illustrates how a binuclear zinc site confers upon metallo-beta-lactamases the ability both to recognize and efficiently hydrolyze a wide variety of beta-lactam substrates.
Collapse
Affiliation(s)
- James Spencer
- Departments of Cellular and Molecular Medicine and Biochemistry, University of Bristol School of Medical Sciences, University Walk, Bristol BS8 1TD, United Kingdom
| | | | | | | | | | | |
Collapse
|
40
|
Abstract
Direct fluorination of arenemethanesulfonamide anions under mild conditions and in high yield has been accomplished using N-fluorobisbenzenesulfonimide, NFSi, on carbanions of N-tert-butyl- and N-bis-(4-methoxyphenyl-methyl)-benzenemethanesulfonamides giving novel alpha-fluoro- and alpha,alpha-difluoro-benzenemethanesulfonamides respectively: IC(50) and pK(a) data show that alpha-halogenation enhances sulfonamide acidity incrementally and correlates well with increased carbonic anhydrase inhibition, while lipophilicity is also enhanced.
Collapse
Affiliation(s)
- G Michael Blackburn
- University of Sheffield, Department of Chemistry, Sheffield, S3 7HF, England.
| | | |
Collapse
|
41
|
Boyle NA, Chegwidden WR, Blackburn GM. A new synthesis of difluoromethanesulfonamides–a novel pharmacophore for carbonic anhydrase inhibition. Org Biomol Chem 2005; 3:222-4. [PMID: 15632962 DOI: 10.1039/b416642f] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Preparation of the key intermediate carboxydifluoromethanesulfonamide provides direct synthetic access to a wide range of novel difluoromethanesulfonamides, including the acetazolamide analogue (2-ethanoylamino-1,3,4-thiadiazol-5-yl)-difluoromethanesulfonamide. Their water solubility and stability, ether partition coefficient, pK(a) and submicromolar dissociation constants for human carbonic anhydrase isozyme II (HCA II) make them promising candidates for topical glaucoma therapy.
Collapse
Affiliation(s)
- Nicholas A Boyle
- Krebs Institute, Chemistry Department, Sheffield University, Sheffield, UK S3 7HF
| | | | | |
Collapse
|
42
|
Berrisford JM, Akerboom J, Brouns S, Sedelnikova SE, Turnbull AP, van der Oost J, Salmon L, Hardré R, Murray IA, Blackburn GM, Rice DW, Baker PJ. The Structures of Inhibitor Complexes of Pyrococcus furiosus Phosphoglucose Isomerase Provide Insights into Substrate Binding and Catalysis. J Mol Biol 2004; 343:649-57. [PMID: 15465052 DOI: 10.1016/j.jmb.2004.08.061] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2004] [Revised: 08/18/2004] [Accepted: 08/19/2004] [Indexed: 10/26/2022]
Abstract
Pyrococcus furiosus phosphoglucose isomerase (PfPGI) is a metal-containing enzyme that catalyses the interconversion of glucose 6-phosphate (G6P) and fructose 6-phosphate (F6P). The recent structure of PfPGI has confirmed the hypothesis that the enzyme belongs to the cupin superfamily and identified the position of the active site. This fold is distinct from the alphabetaalpha sandwich fold commonly seen in phosphoglucose isomerases (PGIs) that are found in bacteria, eukaryotes and some archaea. Whilst the mechanism of the latter family is thought to proceed through a cis-enediol intermediate, analysis of the structure of PfPGI in the presence of inhibitors has led to the suggestion that the mechanism of this enzyme involves the metal-dependent direct transfer of a hydride between C1 and C2 atoms of the substrate. To gain further insight in the reaction mechanism of PfPGI, the structures of the free enzyme and the complexes with the inhibitor, 5-phospho-d-arabinonate (5PAA) in the presence and absence of metal have been determined. Comparison of these structures with those of equivalent complexes of the eukaryotic PGIs reveals similarities at the active site in the disposition of possible catalytic residues. These include the presence of a glutamic acid residue, Glu97 in PfPGI, which occupies the same position relative to the inhibitor as that of the glutamate that is thought to function as the catalytic base in the eukaryal-type PGIs. These similarities suggest that aspects of the catalytic mechanisms of these two structurally unrelated PGIs may be similar and based on an enediol intermediate.
Collapse
Affiliation(s)
- John M Berrisford
- The Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Krakowiak A, Pace HC, Blackburn GM, Adams M, Mekhalfia A, Kaczmarek R, Baraniak J, Stec WJ, Brenner C. Biochemical, crystallographic, and mutagenic characterization of hint, the AMP-lysine hydrolase, with novel substrates and inhibitors. J Biol Chem 2004; 279:18711-6. [PMID: 14982931 PMCID: PMC2556070 DOI: 10.1074/jbc.m314271200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hint, histidine triad nucleotide-binding protein, is a universally conserved enzyme that hydrolyzes AMP linked to lysine and, in yeast, functions as a positive regulator of the RNA polymerase II C-terminal domain kinase, Kin28. To explore the biochemical and structural bases for the adenosine phosphoramidate hydrolase activity of rabbit Hint, we synthesized novel substrates linking a p-nitroaniline group to adenylate (AMP-pNA) and inhibitors that consist of an adenosine group and 5'-sulfamoyl (AdoOSO(2)NH(2)) or N-ethylsulfamoyl (AdoOSO(2)NHCH(2)CH(3)) group. AMP-pNA is a suitable substrate for Hint that allowed characterization of the inhibitors; titration of each inhibitor into AMP-pNA assays revealed their K(i) values. The N-ethylsulfamoyl derivative has a 13-fold binding advantage over the sulfamoyl adenosine. The 1.8-A cocrystal structure of rabbit Hint with N-ethylsulfamoyl adenosine revealed a binding site for the ethyl group against Trp-123, a residue that reaches across the Hint dimer interface to interact with the alkyl portion of the inhibitor and, presumably, the alkyl portion of a lysyl substrate. Ser-107 is positioned to donate a hydrogen bond to the leaving group nitrogen. Consistent with a role in acid-base catalysis, the Hint S107A mutant protein displayed depressed catalytic activity.
Collapse
Affiliation(s)
- Agnieszka Krakowiak
- Structural Biology and Bioinformatics Program, Kimmel Cancer Center, Philadelphia, Pennsylvania 19107, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Muranova TA, Ruzheinikov SN, Higginbottom A, Clipson JA, Blackburn GM, Wentworth P, Datta A, Rice DW, Partridge LJ. Crystallization of a carbamatase catalytic antibody Fab fragment and its complex with a transition-state analogue. Acta Crystallogr D Biol Crystallogr 2003; 60:172-4. [PMID: 14684920 DOI: 10.1107/s0907444903026350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2003] [Accepted: 11/01/2003] [Indexed: 11/11/2022]
Abstract
Catalytic antibodies showing carbamatase activity have significant potential in antibody-directed prodrug therapy against tumours. The Fab fragment of an IgG1 mouse monoclonal carbamatase catalytic antibody JC1 raised against a transition-state analogue, ethyl N-(3,5-dicarboxyphenyl)-P-[N-[5'-(2",5"-dioxo-1"-pyrrolidinyl)oxy-1',5'-dioxopentyl]-4-aminophenylmethyl]phosphonamidate, was obtained by digestion of the whole antibody with papain and was purified by two-step ion-exchange chromatography. Using hanging-drop vapour-diffusion crystallization techniques, three different crystal forms of the Fab fragment were obtained in the presence and absence of the transition-state analogue. All crystals diffract X-rays to between 3.5 and 3.2 A resolution. The two crystal forms grown in the presence of the transition-state analogue contain up to four or eight copies of the Fab in the asymmetric unit and diffract to 3.5 and 3.2 A, respectively. The crystal of the Fab alone is most likely to contain only two copies of the Fab in the asymmetric unit and diffracts to beyond 3.5 A. Determination of the structure will provide insights into the active-site arrangement of this antibody and will help to increase our understanding of the molecular mechanisms by which the immune system can evolve catalytic function.
Collapse
Affiliation(s)
- Tatyana A Muranova
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, England
| | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Spelta V, Mekhalfia A, Rejman D, Thompson M, Blackburn GM, North RA. ATP analogues with modified phosphate chains and their selectivity for rat P2X2 and P2X2/3 receptors. Br J Pharmacol 2003; 140:1027-34. [PMID: 14581175 PMCID: PMC1574118 DOI: 10.1038/sj.bjp.0705531] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. Heteromeric P2X2/3 receptors are much more sensitive than homomeric P2X2 receptors to alphabeta-methylene-ATP, and this ATP analogue is widely used to discriminate the two receptors on sensory neurons and other cells. 2. We sought to determine the structural basis for this selectivity by synthesising ADP and ATP analogues in which the alphabeta and/or betagamma oxygen atoms were replaced by other moieties (including -CH2-, -CHF-, -CHCl-, -CHBr-, -CF2-, -CCl2-, -CBr2-, -CHSO3-, -CHPO3-, -CFPO3-, -CClPO3-, -CH2-CH2-, C triple bond C, -NH-, -CHCOOH-). 3. We tested their actions as agonists or antagonists by whole-cell recording from human embryonic kidney cells expressing P2X2 subunits alone (homomeric P2X2 receptors), or cells expressing both P2X2 and P2X3 subunits, in which the current through heteromeric P2X2/3 receptors was isolated. 4. ADP analogues had no agonist or antagonist effect at either P2X2 or P2X2/3 receptors. All the ATP analogues tested were without agonist or antagonist activity at homomeric P2X2 receptors, except betagamma-difluoromethylene-ATP, which was a weak agonist. 5. At P2X2/3 receptors, betagamma-imido-ATP, betagamma-methylene-ATP, and betagamma-acetylene-ATP were weak agonists, whereas alphabeta,betagamma- and betagamma,gammadelta-bismethylene-AP4 were potent full agonists. betagamma-Carboxymethylene-ATP and betagamma-chlorophosphonomethylene-ATP were weak antagonists at P2X2/3 receptors (IC50 about 10 microm). 6. The results indicate (a). that the homomeric P2X2 receptor presents very stringent structural requirements with respect to its activation by ATP; (b). that the heteromeric P2X2/3 receptor is much more tolerant of alphabeta and betagamma substitution; and (c). that a P2X2/3-selective antagonist can be obtained by introduction of additional negativity at the betagamma-methylene.
Collapse
Affiliation(s)
- Valeria Spelta
- Institute of Molecular Physiology, University of Sheffield, Sheffield S10 2TN
| | | | - Dominik Rejman
- Department of Chemistry, University of Sheffield, Sheffield S10 2TN
| | - Mark Thompson
- Department of Chemistry, University of Sheffield, Sheffield S10 2TN
| | | | - R Alan North
- Institute of Molecular Physiology, University of Sheffield, Sheffield S10 2TN
- Author for correspondence:
| |
Collapse
|
46
|
Ruzheinikov SN, Muranova TA, Sedelnikova SE, Partridge LJ, Blackburn GM, Murray IA, Kakinuma H, Takahashi-Ando N, Shimazaki K, Sun J, Nishi Y, Rice DW. High-resolution crystal structure of the Fab-fragments of a family of mouse catalytic antibodies with esterase activity. J Mol Biol 2003; 332:423-35. [PMID: 12948492 DOI: 10.1016/s0022-2836(03)00902-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The crystal structures of four related Fab fragments of a family of catalytic antibodies displaying differential levels of esterase activity have been solved in the presence and in the absence of the transition-state analogue (TSA) that was used to elicit the immune response. The electron density maps show that the TSA conformation is essentially identical, with limited changes on hapten binding. Interactions with the TSA explain the specificity for the D rather than the L-isomer of the substrate. Differences in the residues in the hapten-binding pocket, which increase hydrophobicity, appear to correlate with an increase in the affinity of the antibodies for their substrate. Analysis of the structures at the active site reveals a network of conserved hydrogen bond contacts between the TSA and the antibodies, and points to a critical role of two conserved residues, HisL91 and LysH95, in catalysis. However, these two key residues are set into very different contexts in their respective structures, with an apparent direct correlation between the catalytic power of the antibodies and the complexity of their interactions with the rest of the protein. This suggests that the catalytic efficiency may be controlled by contacts arising from a second sphere of residues at the periphery of the active site.
Collapse
Affiliation(s)
- Sergey N Ruzheinikov
- Krebs Institute for Biomolecular Research, University of Sheffield, Firth Court, Western Bank, S10 2TN Sheffield, UK
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Blackburn GM, Williams NH, Gamblin SJ, Smerdon SJ. Comment on "The pentacovalent phosphorus intermediate of a phosphoryl transfer reaction". Science 2003; 301:1184; author reply 1184. [PMID: 12947182 DOI: 10.1126/science.1085796] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
48
|
Cesaro-Tadic S, Lagos D, Honegger A, Rickard JH, Partridge LJ, Blackburn GM, Plückthun A. Turnover-based in vitro selection and evolution of biocatalysts from a fully synthetic antibody library. Nat Biotechnol 2003; 21:679-85. [PMID: 12754520 DOI: 10.1038/nbt828] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2002] [Accepted: 02/21/2003] [Indexed: 11/08/2022]
Abstract
This report describes the selection of highly efficient antibody catalysts by combining chemical selection from a synthetic library with directed in vitro protein evolution. Evolution started from a naive antibody library displayed on phage made from fully synthetic, antibody-encoding genes (the Human Combinatorial Antibody Library; HuCAL-scFv). HuCAL-scFv was screened by direct selection for catalytic antibodies exhibiting phosphatase turnover. The substrate used was an aryl phosphate, which is spontaneously transformed into an electrophilic trapping reagent after cleavage. Chemical selection identified an efficient biocatalyst that then served as a template for error-prone PCR (epPCR) to generate randomized repertoires that were subjected to further selection cycles. The resulting superior catalysts displayed cumulative mutations throughout the protein sequence; the ten-fold improvement of their catalytic proficiencies (>10(10) M(-1)) resulted from increased kcat values, thus demonstrating direct selection for turnover. The strategy described here makes the search for new catalysts independent of the immune system and the antibody framework.
Collapse
Affiliation(s)
- Sandro Cesaro-Tadic
- Biochemisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | | | | | | | | | | | | |
Collapse
|
49
|
Hinckley GT, Ruzicka FJ, Thompson MJ, Blackburn GM, Frey PA. Adenosyl coenzyme and pH dependence of the [4Fe-4S]2+/1+ transition in lysine 2,3-aminomutase. Arch Biochem Biophys 2003; 414:34-9. [PMID: 12745252 DOI: 10.1016/s0003-9861(03)00160-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
5'-[N-[(3S)-3-Amino-carboxypropyl]-N-methylamino]-5(')-deoxyadenosine (azaSAM), an analog of S-adenosyl-L-methionine (SAM), was used to study the cofactor-dependent reduction of the [4Fe-4S](2+) center in lysine 2,3-aminomutase to the +1 oxidation state. azaSAM has a tertiary nitrogen in place of the sulfonium center of SAM. The analog binds to lysine 2,3-aminomutase with K(d)s of 1.4+/-0.3 microM at pH 8.0 and 2.2+/-0.6 microM at pH 6.5. Reduction of the [4Fe-4S](2+) center in the presence of this analog gives a 10K [4Fe-4S](1+) electron paramagnetic resonance (EPR) signal similar to that seen with SAM or S-adenosyl-L-homocysteine (SAH). The pH dependence of cofactor-induced reduction was examined to determine whether ionization of the tertiary nitrogen (pK(a)=7.08) might affect reduction of the [4Fe-4S](2+) center. The results show similar behavior in azaSAM and SAH, demonstrating that ionization of the aza group in azaSAM does not account for pH dependence in cofactor-dependent reduction of the [4Fe-4S](2+) center. The signal shape of the low-temperature EPR signal for the [4Fe-4S](1+) center in the SAM-induced reduction displayed a pH dependence that was not observed in the azaSAM- or SAH-induced spectra. Unique features of the signal are at a maximum at the pH activity optimum of pH 8 and are diminished as the pH is lowered or raised. These features are also absent in the spectra at all pHs examined when reduction is induced by azaSAM or SAH.
Collapse
Affiliation(s)
- Glen T Hinckley
- Department of Biochemistry, University of Wisconsin - Madison, 53705, USA
| | | | | | | | | |
Collapse
|
50
|
Verspohl EJ, Blackburn GM, Hohmeier N, Hagemann J, Lempka M. Synthetic, nondegradable diadenosine polyphosphates and diinosine polyphosphates: their effects on insulin-secreting cells and cultured vascular smooth muscle cells. J Med Chem 2003; 46:1554-62. [PMID: 12672257 DOI: 10.1021/jm011070z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Diadenosine polyphosphates show a dissimilarity between their effects in static and perifusion experiments with respect to insulin release that may be due to degradation of the compounds. The aim was to investigate two nondegradable compounds of bisphosphorothioates containing a methylene or chloromethylene group (namely, diadenosine 5',5' "-(P(1),P(4)-dithio-P(2),P(3)-methylene)tetraphosphate and diadenosine 5',5' "-(P(1),P(4)-dithio-P(2),P(3)-chloromethylene)tetraphosphate), as mixtures of three or four diastereomers. Owing to their modified structures, these compounds are resistant to degradation (ectophosphodiesterases, diphosphohydrolases, and phosphorylases). Both compounds tested were minimally degraded (2%) even after 16 h when incubated with insulin-secreting (INS-1) cells. Additionally, diinosine polyphosphates (Ip(5)I and Ip(6)I), putative antagonists of diadenosine polyphosphates, were tested. By use of [(3)H]Ap(4)A, saturable binding sites for both diadenosine polyphosphate analogues were found in INS-1 cells, 3T3 preadipocyte cells, and vascular smooth muscle cells (VSMC) and for both Ip(5)I and Ip(6)I in INS-1 cells. The synthesized diadenosine polyphosphate analogues have the same affinity as Ap(4)A, whereas Ip(5)I and Ip(6)I inhibit binding at higher concentrations (10-100 microM). Insulin release was investigated in static experiments over 90 min in INS-1 cells. Insulin release was inhibited dose-dependently by both of the diadenosine polyphosphate analogues to the same degree as by Ap(4)A. The glucose-induced insulin release curve was not shifted to the right. Both compounds inhibit insulin release only at high (insulin stimulatory) glucose concentrations, e.g., 5.6 mM glucose. Ip(5)I and Ip(6)I antagonized Ap(5)A-mediated inhibition of insulin release. [(3)H]Thymidine incorporation into VSMC was not influenced by either synthetic diadenosine polyphosphate analogue, indicating that Ap(4)A does not act by itself in this case but (active) degradation products mediate the effect. The data indicate the following. (1) Since nondegradable compounds inhibit insulin release as well as Ap(4)A, it is Ap(4)A itself and not any of its degradation products that induces this effect. (2) Diadenosine polyphosphate effects on cell proliferation are mediated via a degradation product in contrast to their effect on insulin release. (3) Ip(5)I and Ip(6)I act like antagonists. Both synthetic analogues and diinosine polyphosphates are valuable tools for diabetes research.
Collapse
Affiliation(s)
- Eugen J Verspohl
- Department of Pharmacology, Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Hittorfstrasse 58-62, Germany.
| | | | | | | | | |
Collapse
|