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Relations between Structure and Zn(II) Binding Affinity Shed Light on the Mechanisms of Rad50 Hook Domain Functioning and Its Phosphorylation. Int J Mol Sci 2022; 23:ijms231911140. [PMID: 36232441 PMCID: PMC9569753 DOI: 10.3390/ijms231911140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/17/2022] [Accepted: 09/19/2022] [Indexed: 11/16/2022] Open
Abstract
The metal binding at protein–protein interfaces is still uncharted territory in intermolecular interactions. To date, only a few protein complexes binding Zn(II) in an intermolecular manner have been deeply investigated. The most notable example of such interfaces is located in the highly conserved Rad50 protein, part of the Mre11-Rad50-Nbs1 (MRN) complex, where Zn(II) is required for homodimerization (Zn(Rad50)2). The high stability of Zn(Rad50)2 is conserved not only for the protein derived from the thermophilic archaeon Pyrococcus furiosus (logK12 = 20.95 for 130-amino-acid-long fragment), which was the first one studied, but also for the human paralog studied here (logK12 = 19.52 for a 183-amino-acid-long fragment). As we reported previously, the extremely high stability results from the metal-coupled folding process where particular Rad50 protein fragments play a critical role. The sequence–structure–stability analysis based on human Rad50 presented here separates the individual structural components that increase the stability of the complex, pointing to amino acid residues far away from the Zn(II) binding site as being largely responsible for the complex stabilization. The influence of the individual components is very well reflected by the previously published crystal structure of the human Rad50 zinc hook (PDB: 5GOX). In addition, we hereby report the effect of phosphorylation of the zinc hook domain, which exerts a destabilizing effect on the domain. This study identifies factors governing the stability of metal-mediated protein–protein interactions and illuminates their molecular basis.
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2
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Elvers BJ, Krewald V, Schulzke C, Fischer C. Reduction induced S-nucleophilicity in mono-dithiolene molybdenum complexes - in situ generation of sulfonium ligands. Chem Commun (Camb) 2021; 57:12615-12618. [PMID: 34755726 DOI: 10.1039/d1cc05335c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reduction of a molybdenum monodithiolene complex, [Mo(CO)2(dt)(dppe)], in the presence of dichloromethane leads to the transfer of CH2 to sulfur and respective sulfonium species. Detailed analytical and mechanistical spectroscopic and electrochemical studies reveal the reasons for the unexpected formation and composition of the very unusual resultant complexes to be electronic-energetic in nature.
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Affiliation(s)
- Benedict J Elvers
- Universität Greifswald, Institut für Biochemie, Felix-Hausdorff-Str. 4, Greifswald, Germany.
| | - Vera Krewald
- Technische Universität Darmstadt, Fachbereich Chemie, Theoretische Chemie, Alarich-Weiss-Str. 4, 64287 Darmstadt, Germany.
| | - Carola Schulzke
- Universität Greifswald, Institut für Biochemie, Felix-Hausdorff-Str. 4, Greifswald, Germany.
| | - Christian Fischer
- Universität Greifswald, Institut für Biochemie, Felix-Hausdorff-Str. 4, Greifswald, Germany.
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3
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Yang W, Wang K, Wu H, Shao H, Chen H, Zhu J. Peptide scaffold‐derived peptidomimetic farnesyltransferase inhibitors. J CHIN CHEM SOC-TAIP 2021. [DOI: 10.1002/jccs.202100037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Wei Yang
- Department of Infectious Diseases, Taizhou Hospital Zhejiang University Taizhou China
| | - Kuifeng Wang
- Department of Infectious Diseases, Taizhou Hospital Zhejiang University Taizhou China
| | - Hongwei Wu
- Department of Infectious Diseases Affiliated Taizhou Hospital of Wenzhou Medical University Taizhou China
| | - Hui Shao
- Department of Infectious Diseases, Taizhou Hospital Zhejiang University Taizhou China
| | - Huazhong Chen
- Department of Infectious Diseases, Taizhou Hospital Zhejiang University Taizhou China
| | - Jiansheng Zhu
- Department of Infectious Diseases, Taizhou Hospital Zhejiang University Taizhou China
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4
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Wang Q, Chen F, Liu P, Mu Y, Sun S, Yuan X, Shang P, Ji B. Scaffold-based analysis of nonpeptide oncogenic FTase inhibitors using multiple similarity matching, binding affinity scoring and enzyme inhibition assay. J Mol Graph Model 2021; 105:107898. [PMID: 33784524 DOI: 10.1016/j.jmgm.2021.107898] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/25/2021] [Accepted: 03/05/2021] [Indexed: 10/21/2022]
Abstract
Oncogenic protein farnesyltransferase (FTase) is a key enzyme responsible for the lipid modification of a large and important number of proteins including Ras, which has been recognized as a druggable target of diverse cancers. Here, we report a systematic scaffold-based analysis to investigate the affinity, selectivity and cross-reactivity of nonpeptide inhibitors across ontology-enriched, disease-associated FTase mutants, by integrating multiple similarity matching, binding affinity scoring and enzyme inhibition assay. It is revealed that nonpeptide inhibitors are generally insensitive to FTase mutations; many of them cannot definitely select for wild-type target over mutant enzymes. Therefore, off-target is observed as a common phenomenon for the untargeted consequence of targeted therapies with FTase inhibition. This is not unexpected if considering that the enzyme active site is highly conserved in composition, configuration and function. The off-target, on the one hand, causes nonpeptide inhibitors with adverse drug reactions and, on the other hand, makes the inhibitors as promising candidates for the new use of old drugs. To practice the latter, a number of unexpected mutant-inhibitor interactions involved in cancer signaling pathways are uncovered in the created profile, from which several nonpeptide inhibitors are identified as insensitive to a drug-resistant mutation. Structural analysis suggests that the inhibitor ligands can bind to the mutant active site in a similar manner with wild-type target, although their nonbonded interactions appear to be impaired moderately upon the mutation.
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Affiliation(s)
- Qifei Wang
- Department of Chest Surgery, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, China
| | - Fei Chen
- Department of Gastroenterology, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, China
| | - Peng Liu
- Department of Chest Surgery, Ningyang First People's Hospital, Taian, 271400, China
| | - Yushu Mu
- Department of Chest Surgery, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, China
| | - Shibin Sun
- Department of Chest Surgery, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, China
| | - Xulong Yuan
- Department of Chest Surgery, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, China
| | - Pan Shang
- Department of Chest Surgery, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, China
| | - Bo Ji
- Department of Chest Surgery, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, China.
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5
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McCubbin Stepanic O, Ward J, Penner-Hahn JE, Deb A, Bergmann U, DeBeer S. Probing a Silent Metal: A Combined X-ray Absorption and Emission Spectroscopic Study of Biologically Relevant Zinc Complexes. Inorg Chem 2020; 59:13551-13560. [PMID: 32893611 PMCID: PMC7509839 DOI: 10.1021/acs.inorgchem.0c01931] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
As the second most common transition metal in the human body, zinc is of great interest to research but has few viable routes for its direct structural study in biological systems. Herein, Zn valence-to-core X-ray emission spectroscopy (VtC XES) and Zn K-edge X-ray absorption spectroscopy (XAS) are presented as a means to understand the local structure of zinc in biological systems through the application of these methods to a series of biologically relevant molecular model complexes. Taken together, the Zn K-edge XAS and VtC XES provide a means to establish the ligand identity, local geometry, and metal-ligand bond lengths. Experimental results are supported by correlation with density-functional-theory-based calculations. Combining these theoretical and experimental approaches will enable future applications to protein systems in a predictive manner.
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Affiliation(s)
- Olivia McCubbin Stepanic
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Jesse Ward
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - James E Penner-Hahn
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Aniruddha Deb
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Uwe Bergmann
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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6
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Wu YY, Hong JC, Tsai RF, Pan HR, Huang BH, Chiang YW, Lee GH, Cheng MJ, Hsu HF. Ligand-Based Reactivity of Oxygenation and Alkylation in Cobalt Complexes Binding with (Thiolato)phosphine Derivatives. Inorg Chem 2020; 59:4650-4660. [PMID: 32186861 DOI: 10.1021/acs.inorgchem.9b03740] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In our efforts to understand the nature of metal thiolates, we have explored the chemistry of cobalt ion supported by (thiolato)phosphine ligand derivatives. Herein, we synthesized and characterized a square-planar CoII complex binding with a bidentate (thiolato)phosphine ligand, Co(PS1″)2 (1) ([PS1″]- = [P(Ph)2(C6H3-3-SiMe3-2-S)]-). The complex activates O2 to form a ligand-based oxygenation product, Co(OPS1″)2 (2) ([OPS1″]- = [PO(Ph)2(C6H3-3-SiMe3-2-S)]-). In addition, an octahedral CoIII complex with a tridentate bis(thiolato)phosphine ligand, [NEt4][Co(PS2*)2] (3) ([PS2*]2- = [P(Ph)(C6H3-3-Ph-2-S)2]2-), was obtained. Compound 3 cleaves the C-Cl bond in dichloromethane via an S-based nucleophilic attack to generate a chloromethyl thioether group. Two isomeric products, [Co(PS2*)(PSSCH2Cl*)] (4 and 4') ([PSSCH2Cl*]- = [P(Ph)(C6H3-3-Ph-2-S)(C6H3-3-Ph-2-SCH2Cl)]-), were isolated and fully characterized. Both transformations, oxygenation of a CoII-bound phosphine donor in 1 and alkylation of a CoIII-bound thiolate in 3, were monitored by spectroscopic methods. These reaction products were isolated and fully characterized. Density functional theory (DFT, the B3LYP functional) calculations were performed to understand the electronic structure of 1 as well as the pathway of its transformation to 2.
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Affiliation(s)
- Yi-Ying Wu
- Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan
| | - Jia-Cheng Hong
- Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan
| | - Ruei-Fong Tsai
- Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Hung-Ruei Pan
- Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan
| | - Bo-Hua Huang
- Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan
| | - Yun-Wei Chiang
- Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Gene-Hsiang Lee
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan
| | - Mu-Jeng Cheng
- Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan
| | - Hua-Fen Hsu
- Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan
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7
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Witkowska D, Rowińska-Żyrek M. Biophysical approaches for the study of metal-protein interactions. J Inorg Biochem 2019; 199:110783. [PMID: 31349072 DOI: 10.1016/j.jinorgbio.2019.110783] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/10/2019] [Accepted: 07/15/2019] [Indexed: 12/17/2022]
Abstract
Protein-protein interactions play important roles for a variety of cell functions, often involving metal ions; in fact, metal-ion binding mediates and regulates the activity of a wide range of biomolecules. Enlightening all of the specific features of metal-protein and metal-mediated protein-protein interactions can be a very challenging task; a detailed knowledge of the thermodynamic and spectroscopic parameters and the structural changes of the protein is normally required. For this purpose, many experimental techniques are employed, embracing all fields of Analytical and Bioinorganic Chemistry. In addition, the use of peptide models, reproducing the primary sequence of the metal-binding sites, is also proved to be useful. In this paper, a review of the most useful techniques for studying ligand-protein interactions with a special emphasis on metal-protein interactions is provided, with a critical summary of their strengths and limitations.
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Affiliation(s)
- Danuta Witkowska
- Public Higher Medical Professional School in Opole, Katowicka 68, 45060 Opole, Poland.
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8
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Moorthy NSHN, Sousa SF, Ramos MJ, Fernandes PA. Binding mode of conformations and structure-based pharmacophore development for farnesyltransferase inhibitors. Med Chem Res 2016. [DOI: 10.1007/s00044-016-1578-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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9
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Moorthy NSHN, Sousa SF, Ramos MJ, Fernandes PA. Molecular dynamic simulations and structure-based pharmacophore development for farnesyltransferase inhibitors discovery. J Enzyme Inhib Med Chem 2016; 31:1428-42. [PMID: 26887913 DOI: 10.3109/14756366.2016.1144593] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Farnesyltransferase is one of the enzyme targets for the development of drugs for diseases, including cancer, malaria, progeria, etc. In the present study, the structure-based pharmacophore models have been developed from five complex structures (1LD7, 1NI1, 2IEJ, 2ZIR and 2ZIS) obtained from the protein data bank. Initially, molecular dynamic (MD) simulations were performed for the complexes for 10 ns using AMBER 12 software. The conformers of the complexes (75) generated from the equilibrated protein were undergone protein-ligand interaction fingerprint (PLIF) analysis. The results showed that some important residues, such as LeuB96, TrpB102, TrpB106, ArgB202, TyrB300, AspB359 and TyrB361, are predominantly present in most of the complexes for interactions. These residues form side chain acceptor and surface (hydrophobic or π-π) kind of interactions with the ligands present in the complexes. The structure-based pharmacophore models were generated from the fingerprint bits obtained from PLIF analysis. The pharmacophore models have 3-4 pharmacophore contours consist of acceptor and metal ligation (Acc & ML), hydrophobic (HydA) and extended acceptor (Acc2) features with the radius ranging between 1-3 Å for Acc & ML and 1-2 Å for HydA. The excluded volumes of the pharmacophore contours radius are between 1-2 Å. Further, the distance between the interacting groups, root mean square deviation (RMSD), root mean square fluctuation (RMSF) and radial distribution function (RDF) analysis were performed for the MD-simulated proteins using PTRAJ module. The generated pharmacophore models were used to screen a set of natural compounds and database compounds to select significant HITs. We conclude that the developed pharmacophore model can be a significant model for the identification of HITs as FTase inhibitors.
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Affiliation(s)
- N S Hari Narayana Moorthy
- a UCIBIO, REQUIMTE, Departamento de Química e Bioquímica, Universidade do Porto , 687, Rua do Campo Alegre , Porto , Portugal
| | - Sergio F Sousa
- a UCIBIO, REQUIMTE, Departamento de Química e Bioquímica, Universidade do Porto , 687, Rua do Campo Alegre , Porto , Portugal
| | - Maria J Ramos
- a UCIBIO, REQUIMTE, Departamento de Química e Bioquímica, Universidade do Porto , 687, Rua do Campo Alegre , Porto , Portugal
| | - Pedro A Fernandes
- a UCIBIO, REQUIMTE, Departamento de Química e Bioquímica, Universidade do Porto , 687, Rua do Campo Alegre , Porto , Portugal
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10
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Palsuledesai CC, Distefano MD. Protein prenylation: enzymes, therapeutics, and biotechnology applications. ACS Chem Biol 2015; 10:51-62. [PMID: 25402849 PMCID: PMC4301080 DOI: 10.1021/cb500791f] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
![]()
Protein
prenylation is a ubiquitous covalent post-translational modification
found in all eukaryotic cells, comprising attachment of either a farnesyl
or a geranylgeranyl isoprenoid. It is essential for the proper cellular
activity of numerous proteins, including Ras family GTPases and heterotrimeric
G-proteins. Inhibition of prenylation has been extensively investigated
to suppress the activity of oncogenic Ras proteins to achieve antitumor
activity. Here, we review the biochemistry of the prenyltransferase
enzymes and numerous isoprenoid analogs synthesized to investigate
various aspects of prenylation and prenyltransferases. We also give
an account of the current status of prenyltransferase inhibitors as
potential therapeutics against several diseases including cancers,
progeria, aging, parasitic diseases, and bacterial and viral infections.
Finally, we discuss recent progress in utilizing protein prenylation
for site-specific protein labeling for various biotechnology applications.
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Affiliation(s)
- Charuta C. Palsuledesai
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Mark D. Distefano
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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11
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Janssen FFBJ, Peters LCJM, Schlebos PPJ, Smits JMM, de Gelder R, Rowan AE. Uncorrelated Dynamical Processes in Tetranuclear Carboxylate Clusters Studied by Variable-Temperature 1H NMR Spectroscopy. Inorg Chem 2013; 52:13004-13. [DOI: 10.1021/ic401522v] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Femke F. B. J. Janssen
- Institute for Molecules and
Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Laurens C. J. M. Peters
- Institute for Molecules and
Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Paul P. J. Schlebos
- Institute for Molecules and
Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Jan M. M. Smits
- Institute for Molecules and
Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - René de Gelder
- Institute for Molecules and
Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Alan E. Rowan
- Institute for Molecules and
Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
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12
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Chen TT, Chen YS, Chang YH, Wang JC, Tsai YF, Lee GH, Kuo TS, Hsu HF. Activation of dichloromethane by a V(iii) thiolate complex: an example of S-based nucleophilic reactivity in an early transition metal thiolate. Chem Commun (Camb) 2013; 49:1109-11. [DOI: 10.1039/c2cc37801a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Bosc D, Mouray E, Grellier P, Cojean S, Loiseau PM, Dubois J. Introduction of methionine mimics on 3-arylthiophene: influence on protein farnesyltransferase inhibition and on antiparasitic activity. MEDCHEMCOMM 2013. [DOI: 10.1039/c3md00065f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Molecular dynamics analysis of a series of 22 potential farnesyltransferase substrates containing a CaaX-motif. J Mol Model 2012; 19:673-88. [DOI: 10.1007/s00894-012-1590-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 08/29/2012] [Indexed: 10/27/2022]
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15
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A tetrahedral coordination of Zinc during transmembrane transport by P-type Zn(2+)-ATPases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:1374-7. [PMID: 22387457 DOI: 10.1016/j.bbamem.2012.02.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 02/15/2012] [Accepted: 02/17/2012] [Indexed: 01/09/2023]
Abstract
Zn(2+) is an essential transition metal required in trace amounts by all living organisms. However, metal excess is cytotoxic and leads to cell damage. Cells rely on transmembrane transporters, with the assistance of other proteins, to establish and maintain Zn(2+) homeostasis. Metal coordination during transport is key to specific transport and unidirectional translocation without the backward release of free metal. The coordination details of Zn(2+) at the transmembrane metal binding site responsible for transport have now been established. Escherichia coli ZntA is a well-characterized Zn(2+)-ATPase responsible for intracellular Zn(2+) efflux. A truncated form of the protein lacking regulatory metal sites and retaining the transport site was constructed. Metrical parameters of the metal-ligand coordination geometry for the zinc bound isolated form were characterized using x-ray absorption spectroscopy (XAS). Our data support a nearest neighbor ligand environment of (O/N)(2)S(2) that is compatible with the proposed invariant metal coordinating residues present in the transmembrane region. This ligand identification and the calculated bond lengths support a tetrahedral coordination geometry for Zn(2+) bound to the TM-MBS of P-type ATPase transporters.
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16
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Yang Y, Wang B, Ucisik MN, Cui G, Fierke CA, Merz KM. Insights into the mechanistic dichotomy of the protein farnesyltransferase peptide substrates CVIM and CVLS. J Am Chem Soc 2012; 134:820-3. [PMID: 22206225 DOI: 10.1021/ja209650h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protein farnesyltransferase (FTase) catalyzes farnesylation of a variety of peptide substrates. (3)H α-secondary kinetic isotope effect (α-SKIE) measurements of two peptide substrates, CVIM and CVLS, are significantly different and have been proposed to reflect a rate-limiting S(N)2-like transition state with dissociative characteristics for CVIM, while, due to the absence of an isotope effect, CVLS was proposed to have a rate-limiting peptide conformational change. Potential of mean force quantum mechanical/molecular mechanical studies coupled with umbrella sampling techniques were performed to further probe this mechanistic dichotomy. We observe the experimentally proposed transition state (TS) for CVIM but find that CVLS has a symmetric S(N)2 TS, which is also consistent with the absence of a (3)H α-SKIE. These calculations demonstrate facile substrate-dependent alterations in the transition state structure catalyzed by FTase.
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Affiliation(s)
- Yue Yang
- Department of Chemistry and the Quantum Theory Project, 2328 New Physics Building, P.O. Box 118435, University of Florida, Gainesville, Florida 32611-8435, USA
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17
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Bobyr E, Lassila JK, Wiersma-Koch HI, Fenn TD, Lee JJ, Nikolic-Hughes I, Hodgson KO, Rees DC, Hedman B, Herschlag D. High-resolution analysis of Zn(2+) coordination in the alkaline phosphatase superfamily by EXAFS and x-ray crystallography. J Mol Biol 2012; 415:102-17. [PMID: 22056344 PMCID: PMC3249517 DOI: 10.1016/j.jmb.2011.10.040] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 10/21/2011] [Accepted: 10/24/2011] [Indexed: 10/15/2022]
Abstract
Comparisons among evolutionarily related enzymes offer opportunities to reveal how structural differences produce different catalytic activities. Two structurally related enzymes, Escherichia coli alkaline phosphatase (AP) and Xanthomonas axonopodis nucleotide pyrophosphatase/phosphodiesterase (NPP), have nearly identical binuclear Zn(2+) catalytic centers but show tremendous differential specificity for hydrolysis of phosphate monoesters or phosphate diesters. To determine if there are differences in Zn(2+) coordination in the two enzymes that might contribute to catalytic specificity, we analyzed both x-ray absorption spectroscopic and x-ray crystallographic data. We report a 1.29-Å crystal structure of AP with bound phosphate, allowing evaluation of interactions at the AP metal site with high resolution. To make systematic comparisons between AP and NPP, we measured zinc extended x-ray absorption fine structure for AP and NPP in the free-enzyme forms, with AMP and inorganic phosphate ground-state analogs and with vanadate transition-state analogs. These studies yielded average zinc-ligand distances in AP and NPP free-enzyme forms and ground-state analog forms that were identical within error, suggesting little difference in metal ion coordination among these forms. Upon binding of vanadate to both enzymes, small increases in average metal-ligand distances were observed, consistent with an increased coordination number. Slightly longer increases were observed in NPP relative to AP, which could arise from subtle rearrangements of the active site or differences in the geometry of the bound vanadyl species. Overall, the results suggest that the binuclear Zn(2+) catalytic site remains very similar between AP and NPP during the course of a reaction cycle.
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Affiliation(s)
- Elena Bobyr
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | | | | | - Timothy D. Fenn
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Jason J. Lee
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Ivana Nikolic-Hughes
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Keith O. Hodgson
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
- Stanford Synchrotron Radiation Lightsource, SLAC, Stanford University, Menlo Park, CA 94025, USA
| | - Douglas C. Rees
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Britt Hedman
- Stanford Synchrotron Radiation Lightsource, SLAC, Stanford University, Menlo Park, CA 94025, USA
| | - Daniel Herschlag
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
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Gennari M, Gerey B, Hall N, Pécaut J, Vezin H, Collomb MN, Orio M, Duboc C. Structural, spectroscopic and redox properties of a mononuclear CoII thiolate complex – the reactivity toward S-alkylation: an experimental and theoretical study. Dalton Trans 2012; 41:12586-94. [DOI: 10.1039/c2dt31222k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Sousa SF, Fernandes PA, Ramos MJ. Computational enzymatic catalysis – clarifying enzymatic mechanisms with the help of computers. Phys Chem Chem Phys 2012; 14:12431-41. [DOI: 10.1039/c2cp41180f] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Perez MAS, Sousa SF, Oliveira EFT, Fernandes PA, Ramos MJ. Detection of Farnesyltransferase Interface Hot Spots through Computational Alanine Scanning Mutagenesis. J Phys Chem B 2011; 115:15339-54. [DOI: 10.1021/jp205481y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Marta A. S. Perez
- REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
| | - Sérgio F. Sousa
- REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
| | - Eduardo F. T. Oliveira
- REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
| | - Pedro A. Fernandes
- REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
| | - Maria J. Ramos
- REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
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Gennari M, Retegan M, DeBeer S, Pécaut J, Neese F, Collomb MN, Duboc C. Experimental and Computational Investigation of Thiolate Alkylation in NiII and ZnII Complexes: Role of the Metal on the Sulfur Nucleophilicity. Inorg Chem 2011; 50:10047-55. [DOI: 10.1021/ic200899w] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Marcello Gennari
- Université Joseph Fourier Grenoble 1/CNRS, Département de Chimie Moléculaire, UMR-5250, Laboratoire de Chimie Inorganique Redox, Institut de Chimie Moléculaire de Grenoble FR, CNRS-2607, BP-53, 38041 Grenoble Cedex 9, France
| | - Marius Retegan
- Université Joseph Fourier Grenoble 1/CNRS, Département de Chimie Moléculaire, UMR-5250, Laboratoire de Chimie Inorganique Redox, Institut de Chimie Moléculaire de Grenoble FR, CNRS-2607, BP-53, 38041 Grenoble Cedex 9, France
| | - Serena DeBeer
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Jacques Pécaut
- Laboratoire de Reconnaissance Ionique et Chimie de Coordination, Service de Chimie Inorganique et Biologique, UMR E-3 CEA/UJF, CNRS, CEA-Grenoble, INAC, 17 Rue des Martyrs 38054 Grenoble Cedex 9, France
| | - Frank Neese
- Institute for Physical and Theoretical Chemistry, Universität Bonn, Wegelerstrasse 12, D-53113 Bonn, Germany
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Marie-Noëlle Collomb
- Université Joseph Fourier Grenoble 1/CNRS, Département de Chimie Moléculaire, UMR-5250, Laboratoire de Chimie Inorganique Redox, Institut de Chimie Moléculaire de Grenoble FR, CNRS-2607, BP-53, 38041 Grenoble Cedex 9, France
| | - Carole Duboc
- Université Joseph Fourier Grenoble 1/CNRS, Département de Chimie Moléculaire, UMR-5250, Laboratoire de Chimie Inorganique Redox, Institut de Chimie Moléculaire de Grenoble FR, CNRS-2607, BP-53, 38041 Grenoble Cedex 9, France
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22
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Qiao Y, Gao J, Qiu Y, Wu L, Guo F, Kam-Wing Lo K, Li D. Design, synthesis, and characterization of piperazinedione-based dual protein inhibitors for both farnesyltransferase and geranylgeranyltransferase-I. Eur J Med Chem 2011; 46:2264-73. [DOI: 10.1016/j.ejmech.2011.03.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 02/25/2011] [Accepted: 03/02/2011] [Indexed: 01/13/2023]
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23
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Hari Narayana Moorthy NS, Sousa SF, Ramos MJ, Fernandes PA. Structural feature study of benzofuran derivatives as farnesyltransferase inhibitors. J Enzyme Inhib Med Chem 2011; 26:777-91. [DOI: 10.3109/14756366.2011.552885] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- N. S. Hari Narayana Moorthy
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, Porto, Portugal
| | - Sergio F. Sousa
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, Porto, Portugal
| | - Maria J. Ramos
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, Porto, Portugal
| | - Pedro A. Fernandes
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, Porto, Portugal
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Herbst RW, Perovic I, Martin-Diaconescu V, O'Brien K, Chivers PT, Pochapsky SS, Pochapsky TC, Maroney MJ. Communication between the zinc and nickel sites in dimeric HypA: metal recognition and pH sensing. J Am Chem Soc 2010; 132:10338-51. [PMID: 20662514 DOI: 10.1021/ja1005724] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Helicobacter pylori , a pathogen that colonizes the human stomach, requires the nickel-containing metalloenzymes urease and NiFe-hydrogenase to survive this low pH environment. The maturation of both enzymes depends on the metallochaperone, HypA. HypA contains two metal sites, an intrinsic zinc site and a low-affinity nickel binding site. X-ray absorption spectroscopy (XAS) shows that the structure of the intrinsic zinc site of HypA is dynamic and able to sense both nickel loading and pH changes. At pH 6.3, an internal pH that occurs during acid shock, the zinc site undergoes unprecedented ligand substitutions to convert from a Zn(Cys)(4) site to a Zn(His)(2)(Cys)(2) site. NMR spectroscopy shows that binding of Ni(II) to HypA results in paramagnetic broadening of resonances near the N-terminus. NOEs between the beta-CH(2) protons of Zn cysteinyl ligands are consistent with a strand-swapped HypA dimer. Addition of nickel causes resonances from the zinc binding motif and other regions to double, indicating more than one conformation can exist in solution. Although the structure of the high-spin, 5-6 coordinate Ni(II) site is relatively unaffected by pH, the nickel binding stoichiometry is decreased from one per monomer to one per dimer at pH = 6.3. Mutation of any cysteine residue in the zinc binding motif results in a zinc site structure similar to that found for holo-WT-HypA at low pH and is unperturbed by the addition of nickel. Mutation of the histidines that flank the CXXC motifs results in a zinc site structure that is similar to holo-WT-HypA at neutral pH (Zn(Cys)(4)) and is no longer responsive to nickel binding or pH changes. Using an in vitro urease activity assay, it is shown that the recombinant protein is sufficient for recovery of urease activity in cell lysate from a HypA deletion mutant, and that mutations in the zinc-binding motif result in a decrease in recovered urease activity. The results are interpreted in terms of a model wherein HypA controls the flow of nickel traffic in the cell in response to nickel availability and pH.
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Affiliation(s)
- Robert W Herbst
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA
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25
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Sousa SF, Carvalho ES, Ferreira DM, Tavares IS, Fernandes PA, Ramos MJ, Gomes JANF. Comparative analysis of the performance of commonly available density functionals in the determination of geometrical parameters for zinc complexes. J Comput Chem 2010; 30:2752-63. [PMID: 19399915 DOI: 10.1002/jcc.21304] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A set of 44 Zinc-ligand bond-lengths and of 60 ligand-metal-ligand bond angles from 10 diverse transition-metal complexes, representative of the coordination spheres of typical biological Zn systems, were used to evaluate the performance of a total of 18 commonly available density functionals in geometry determination. Five different basis sets were considered for each density functional, namely two all-electron basis sets (a double-zeta and triple-zeta formulation) and three basis sets including popular types of effective-core potentials: Los Alamos, Steven-Basch-Krauss, and Stuttgart-Dresden. The results show that there are presently several better alternatives to the popular B3LYP density functional for the determination of Zn-ligand bond-lengths and angles. BB1K, MPWB1K, MPW1K, B97-2 and TPSS are suggested as the strongest alternatives for this effect presently available in most computational chemistry software packages. In addition, the results show that the use of effective-core potentials (in particular Stuttgart-Dresden) has a very limited impact, in terms of accuracy, in the determination of metal-ligand bond-lengths and angles in Zinc-complexes, and is a good and safe alternative to the use of an all-electron basis set such as 6-31G(d) or 6-311G(d,p).
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Affiliation(s)
- Sérgio F Sousa
- REQUIMTE, Departamento de Química, Faculdade de Ciõncias, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
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26
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Koutmou KS, Casiano-Negroni A, Getz MM, Pazicni S, Andrews AJ, Penner-Hahn JE, Al-Hashimi HM, Fierke CA. NMR and XAS reveal an inner-sphere metal binding site in the P4 helix of the metallo-ribozyme ribonuclease P. Proc Natl Acad Sci U S A 2010; 107:2479-84. [PMID: 20133747 PMCID: PMC2823894 DOI: 10.1073/pnas.0906319107] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Functionally critical metals interact with RNA through complex coordination schemes that are currently difficult to visualize at the atomic level under solution conditions. Here, we report a new approach that combines NMR and XAS to resolve and characterize metal binding in the most highly conserved P4 helix of ribonuclease P (RNase P), the ribonucleoprotein that catalyzes the divalent metal ion-dependent maturation of the 5' end of precursor tRNA. Extended X-ray absorption fine structure (EXAFS) spectroscopy reveals that the Zn(2+) bound to a P4 helix mimic is six-coordinate, with an average Zn-O/N bond distance of 2.08 A. The EXAFS data also show intense outer-shell scattering indicating that the zinc ion has inner-shell interactions with one or more RNA ligands. NMR Mn(2+) paramagnetic line broadening experiments reveal strong metal localization at residues corresponding to G378 and G379 in B. subtilis RNase P. A new "metal cocktail" chemical shift perturbation strategy involving titrations with , Zn(2+), and confirm an inner-sphere metal interaction with residues G378 and G379. These studies present a unique picture of how metals coordinate to the putative RNase P active site in solution, and shed light on the environment of an essential metal ion in RNase P. Our experimental approach presents a general method for identifying and characterizing inner-sphere metal ion binding sites in RNA in solution.
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Molecular Dynamics Simulations: Difficulties, Solutions and Strategies for Treating Metalloenzymes. CHALLENGES AND ADVANCES IN COMPUTATIONAL CHEMISTRY AND PHYSICS 2010. [DOI: 10.1007/978-90-481-3034-4_11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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28
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Naranuntarat A, Jensen LT, Pazicni S, Penner-Hahn JE, Culotta VC. The interaction of mitochondrial iron with manganese superoxide dismutase. J Biol Chem 2009; 284:22633-40. [PMID: 19561359 PMCID: PMC2755670 DOI: 10.1074/jbc.m109.026773] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 06/24/2009] [Indexed: 01/01/2023] Open
Abstract
Superoxide dismutase 2 (SOD2) is one of the rare mitochondrial enzymes evolved to use manganese as a cofactor over the more abundant element iron. Although mitochondrial iron does not normally bind SOD2, iron will misincorporate into Saccharomyces cerevisiae Sod2p when cells are starved for manganese or when mitochondrial iron homeostasis is disrupted by mutations in yeast grx5, ssq1, and mtm1. We report here that such changes in mitochondrial manganese and iron similarly affect cofactor selection in a heterologously expressed Escherichia coli Mn-SOD, but not a highly homologous Fe-SOD. By x-ray absorption near edge structure and extended x-ray absorption fine structure analyses of isolated mitochondria, we find that misincorporation of iron into yeast Sod2p does not correlate with significant changes in the average oxidation state or coordination chemistry of bulk mitochondrial iron. Instead, small changes in mitochondrial iron are likely to promote iron-SOD2 interactions. Iron binds Sod2p in yeast mutants blocking late stages of iron-sulfur cluster biogenesis (grx5, ssq1, and atm1), but not in mutants defective in the upstream Isu proteins that serve as scaffolds for iron-sulfur biosynthesis. In fact, we observed a requirement for the Isu proteins in iron inactivation of yeast Sod2p. Sod2p activity was restored in mtm1 and grx5 mutants by depleting cells of Isu proteins or using a dominant negative Isu1p predicted to stabilize iron binding to Isu1p. In all cases where disruptions in iron homeostasis inactivated Sod2p, we observed an increase in mitochondrial Isu proteins. These studies indicate that the Isu proteins and the iron-sulfur pathway can donate iron to Sod2p.
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Affiliation(s)
- Amornrat Naranuntarat
- From the Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205 and
| | - Laran T. Jensen
- From the Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205 and
| | - Samuel Pazicni
- the Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109
| | | | - Valeria C. Culotta
- From the Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205 and
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Sousa SF, Fernandes PA, Ramos MJ. Molecular dynamics simulations on the critical states of the farnesyltransferase enzyme. Bioorg Med Chem 2009; 17:3369-78. [DOI: 10.1016/j.bmc.2009.03.055] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Revised: 03/16/2009] [Accepted: 03/20/2009] [Indexed: 10/20/2022]
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30
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Sousa S, Fernandes P, Ramos M. The Search for the Mechanism of the Reaction Catalyzed by Farnesyltransferase. Chemistry 2009; 15:4243-7. [DOI: 10.1002/chem.200802745] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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31
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Wellenreuther G, Cianci M, Tucoulou R, Meyer-Klaucke W, Haase H. The ligand environment of zinc stored in vesicles. Biochem Biophys Res Commun 2009; 380:198-203. [PMID: 19171119 DOI: 10.1016/j.bbrc.2009.01.074] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Accepted: 01/14/2009] [Indexed: 11/28/2022]
Abstract
Zinc serves regulatory functions in cells and thus, several mechanisms exist for tight control of its homeostasis. One mechanism is storage in and retrieval from vesicles, so-called zincosomes, but the chemical speciation of zincosomal zinc has remained enigmatic. Here, we determine the intravesicular zinc-coordination in isolated zincosomes in comparison to intact RAW264.7 murine macrophage cells. In elemental maps of a cell monolayer, generated by microbeam X-ray fluorescence, zincosomes were identified as spots of high zinc accumulation. A fingerprint for the binding motif obtained by muXANES (X-ray absorption near edge structure) matches the XANES from isolated vesicles; zinc is not free, but present as a complexed form (average coordination; 1.0 sulfur, 2,5 histidines 30 and 1.0 oxygen), resembling regulatory or catalytic zinc sites in proteins. Such coordination enables reversible binding, acting as a 'zinc sink', facilitating the accumulation of high amounts of zinc against a concentration gradient.
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Affiliation(s)
- Gerd Wellenreuther
- European Molecular Biology Laboratory, Hamburg Outstation, c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany
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Iranzo O, Jakusch T, Lee KH, Hemmingsen L, Pecoraro VL. The correlation of 113Cd NMR and 111mCd PAC spectroscopies provides a powerful approach for the characterization of the structure of Cd(II)-substituted Zn(II) proteins. Chemistry 2009; 15:3761-72. [PMID: 19229934 PMCID: PMC3598615 DOI: 10.1002/chem.200802105] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cd(II) has been used as a probe of zinc metalloenzymes and proteins because of the spectroscopic silence of Zn(II). One of the most commonly used spectroscopic techniques is (113)Cd NMR; however, in recent years (111m)Cd Perturbed Angular Correlation spectroscopy ((111m)Cd PAC) has also been shown to provide useful structural, speciation and dynamics information on Cd(II) complexes and biomolecules. In this article, we show how the joint use of (113)Cd NMR and (111m)Cd PAC spectroscopies can provide detailed information about the Cd(II) environment in thiolate-rich proteins. Specifically we show that the (113)Cd NMR chemical shifts observed for Cd(II) in the designed TRI series (TRI = Ac-G(LKALEEK)(4)G-NH(2)) of peptides vary depending on the proportion of trigonal planar CdS(3) and pseudotetrahedral CdS(3)O species present in the equilibrium mixture. PAC spectra are able to quantify these mixtures. When one compares the chemical shift range for these peptides (from delta = 570 to 700 ppm), it is observed that CdS(3) species have delta 675-700 ppm, CdS(3)O complexes fall in the range delta 570-600 ppm and mixtures of these forms fall linearly between these extremes. If one then determines the pK(a2) values for Cd(II) complexation [pK(a2) is for the reaction Cd[(peptide-H)(2)(peptide)](+)-->Cd(peptide)(3)(-) + 2H(+)] and compares these to the observed chemical shift for the Cd(peptide)(3)(-) complexes, one finds that there is also a direct linear correlation. Thus, by determining the chemical shift value of these species, one can directly assess the metal-binding affinity of the construct. This illustrates how proteins may be able to fine tune metal-binding affinity by destabilizing one metallospecies with respect to another. More important, these studies demonstrate that one may have a broad (113)Cd NMR chemical shift range for a chemical species (e.g., CdS(3)O) which is not necessarily a reflection of the structural diversity within such a four-coordinate species, but rather a consequence of a fast exchange equilibrium between two related species (e.g., CdS(3)O and CdS(3)). This could lead to reinterpretation of the assignments of cadmium-protein complexes and may impact the application of Cd(II) as a probe of Zn(II) sites in biology.
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Affiliation(s)
- Olga Iranzo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055 (USA)
| | - Tamas Jakusch
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055 (USA)
| | - Kyung-Hoon Lee
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055 (USA)
| | - Lars Hemmingsen
- Bioinorganic Chemistry Group, IGM, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark)
| | - Vincent L. Pecoraro
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055 (USA)
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Picot D, Ohanessian G, Frison G. The Alkylation Mechanism of Zinc-Bound Thiolates Depends upon the Zinc Ligands. Inorg Chem 2008; 47:8167-78. [DOI: 10.1021/ic800697s] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Delphine Picot
- Laboratoire des Mécanismes Réactionnels, Département de Chimie, Ecole Polytechnique and CNRS, 91128 Palaiseau Cedex, France
| | - Gilles Ohanessian
- Laboratoire des Mécanismes Réactionnels, Département de Chimie, Ecole Polytechnique and CNRS, 91128 Palaiseau Cedex, France
| | - Gilles Frison
- Laboratoire des Mécanismes Réactionnels, Département de Chimie, Ecole Polytechnique and CNRS, 91128 Palaiseau Cedex, France
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Myers WK, Duesler EN, Tierney DL. Integrated paramagnetic resonance of high-spin Co(II) in axial symmetry: chemical separation of dipolar and contact electron-nuclear couplings. Inorg Chem 2008; 47:6701-10. [PMID: 18605690 DOI: 10.1021/ic800245k] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Integrated paramagnetic resonance, utilizing electron paramagnetic resonance (EPR), NMR, and electron-nuclear double resonance (ENDOR), of a series of cobalt bis-trispyrazolylborates, Co(Tp ( x )) 2, are reported. Systematic substitutions at the ring carbons and on the apical boron provide a unique opportunity to separate through-bond and through-space contributions to the NMR hyperfine shifts for the parent, unsubstituted Tp complex. A simple relationship between the chemical shift difference (delta H - delta Me) and the contact shift of the proton in that position is developed. This approach allows independent extraction of the isotropic hyperfine coupling, A iso, for each proton in the molecule. The Co..H contact coupling energies derived from the NMR, together with the known metrics of the compounds, were used to predict the ENDOR couplings at g perpendicular. Proton ENDOR data is presented that shows good agreement with the NMR-derived model. ENDOR signals from all other magnetic nuclei in the complex ( (14)N, coordinating and noncoordinating, (11)B and (13)C) are also reported.
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Affiliation(s)
- William K Myers
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico 87131, USA
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Sousa SF, Fernandes PA, Ramos MJ. Enzyme Flexibility and the Catalytic Mechanism of Farnesyltransferase: Targeting the Relation. J Phys Chem B 2008; 112:8681-91. [DOI: 10.1021/jp711214j] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sérgio F. Sousa
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
| | - Pedro A. Fernandes
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
| | - Maria João Ramos
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
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36
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Metal active site elasticity linked to activation of homocysteine in methionine synthases. Proc Natl Acad Sci U S A 2008; 105:3286-91. [PMID: 18296644 DOI: 10.1073/pnas.0709960105] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Enzymes possessing catalytic zinc centers perform a variety of fundamental processes in nature, including methyl transfer to thiols. Cobalamin-independent (MetE) and cobalamin-dependent (MetH) methionine synthases are two such enzyme families. Although they perform the same net reaction, transfer of a methyl group from methyltetrahydrofolate to homocysteine (Hcy) to form methionine, they display markedly different catalytic strategies, modular organization, and active site zinc centers. Here we report crystal structures of zinc-replete MetE and MetH, both in the presence and absence of Hcy. Structural investigation of the catalytic zinc sites of these two methyltransferases reveals an unexpected inversion of zinc geometry upon binding of Hcy and displacement of an endogenous ligand in both enzymes. In both cases a significant movement of the zinc relative to the protein scaffold accompanies inversion. These structures provide new information on the activation of thiols by zinc-containing enzymes and have led us to propose a paradigm for the mechanism of action of the catalytic zinc sites in these and related methyltransferases. Specifically, zinc is mobile in the active sites of MetE and MetH, and its dynamic nature helps facilitate the active site conformational changes necessary for thiol activation and methyl transfer.
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Abstract
X-ray absorption spectroscopy (XAS) has emerged as one of the premier tools for investigating the structure and dynamic properties of metals in cells and in metal containing biomolecules. Utilizing the high flux and broad energy range of X-rays supplied by synchrotron light sources, one can selectively excite core electronic transitions in each metal. Spectroscopic signals from these electronic transitions can be used to dissect the chemical architecture of metals in cells, in cellular components, and in biomolecules at varying degrees of structural resolution. With the development of ever-brighter X-ray sources, X-ray methods have grown into applications that can be utilized to provide both a cellular image of the relative distribution of metals throughout the cell as well as a high-resolution picture of the structure of the metal. As these techniques continue to grow in their capabilities and ease of use, so too does the demand for their application by chemists and biochemists interested in studying the structure and dynamics of metals in cells, in cellular organelles, and in metalloproteins.
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Martini D, Ranieri-Raggi M, Sabbatini ARM, Moir AJG, Polizzi E, Mangani S, Raggi A. Characterization of the metallocenter of rabbit skeletal muscle AMP deaminase. A new model for substrate interactions at a dinuclear cocatalytic Zn site. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2007; 1774:1508-18. [PMID: 17991449 DOI: 10.1016/j.bbapap.2007.10.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2007] [Revised: 09/19/2007] [Accepted: 10/03/2007] [Indexed: 11/28/2022]
Abstract
We have previously provided evidence for a dinuclear zinc site in rabbit skeletal muscle AMPD compatible with a (micro-aqua)(micro-carboxylato)dizinc(II) core with an average of two histidine residues at each metal site. XAS of the zinc binding site of the enzyme in the presence of PRN favors a model where PRN is added to the coordination sphere of one of the two zinc ions increasing its coordination number to five. The uncompetitive nature of the inhibition of AMPD by fluoride reveals that the anion probably displaces the nucleophile water molecule terminally coordinated to the catalytic Zn(1) ion at the enzyme C-terminus, following the binding of AMP at the Zn(2) ion located at N-terminus of the enzyme. Thus, the two Zn ions in the AMPD metallocenter operate together as a single catalytic unit, but have independent function, one of them (Zn(1)) acting to polarize the nucleophile water molecule, whilst the other (Zn(2)) acts transiently as a receptor for an activating substrate molecule. The addition of fluoride to AMPD also abolishes the cooperative behaviour induced in the enzyme by the inhibitory effect of ATP at acidic pH that probably resides in the competition with the substrate for an adenine nucleotide specific regulatory site located in the Zn(2) ion binding region and which is responsible for the positive homotropic cooperativity behaviour of AMPD.
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Affiliation(s)
- Daniela Martini
- Dipartimento di Scienze dell'Uomo e dell'Ambiente, Chimica e Biochimica Medica, Università di Pisa, Via Roma 55, 56126 Pisa, Italy
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Tamames B, Sousa SF, Tamames J, Fernandes PA, Ramos MJ. Analysis of zinc-ligand bond lengths in metalloproteins: Trends and patterns. Proteins 2007; 69:466-75. [PMID: 17623850 DOI: 10.1002/prot.21536] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Zinc is one of the biologically most abundant and important metal elements, present in a plethora of enzymes from a broad array of species of all phyla. In this study we report a thorough analysis of the geometrical properties of Zinc coordination spheres performed on a dataset of 994 high quality protein crystal structures from the Protein Data Bank, and complemented with Quantum mechanical calculations at the DFT level of theory (B3LYP/SDD) on mononuclear model systems. The results allowed us to draw interesting conclusions on the structural characteristics of Zn centres and to evaluate the importance of such effects as the resolution of X-ray crystallographic structures, the enzyme class in which the Zn centre is included, and the identity of the ligands at the Zn coordination sphere. Altogether, the set of results obtained provides useful data for the enhancement of the atomic models normally applied to the theoretical and computational study of zinc enzymes at the quantum mechanical level (in particular enzymatic mechanisms), and for the development of molecular mechanical parameters for the treatment of zinc coordination spheres with molecular mechanics or molecular dynamics in studies with the full enzyme.
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Affiliation(s)
- Bruno Tamames
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal
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Sousa SF, Fernandes PA, Ramos MJ. Comparative assessment of theoretical methods for the determination of geometrical properties in biological zinc complexes. J Phys Chem B 2007; 111:9146-52. [PMID: 17602523 DOI: 10.1021/jp072538y] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In the present study, we have compared the performance of the density functional theory (DFT) functionals B1B95, B3LYP, B97-2, BP86, and BPW91 with MP2 for geometry determination in biological mononuclear Zn complexes. A total of 15 different basis sets, of rather diverse complexity, were tested, several which included also three different types of common effective-core potentials: Los Alamos, Steven-Basch-Krauss, and Stuttgart-Dresden. In addition, the ability to describe mononuclear Zn biological systems using relatively simple models of the metal coordination sphere, comprising only the metal atom and a simplified representation of the ligands at the first coordination sphere, starting from a set of high-resolution X-ray crystallographic structures, is evaluated for 90 combinations of method/basis set. The results show that the use of such models allows for a relatively accurate description of the Zn-ligand bond lengths, although failing to correctly represent the topology of the metal coordination sphere (namely, the angles involving the metal atom) if constraints at the Calpha atoms are not considered. Globally, B3LYP had the best average performance in the test, closely followed by MP2, whereas B1B95 was the least accurate method. The study also points out B3LYP/CEP-121G and B3LYP/SDD, which use, respectively, the Steven-Basch-Krauss and the Stuttgart-Dresden effective-core potentials, as the best compromise between accuracy and CPU time for the geometrical characterization of metal-ligand bond lengths in Zn biological systems.
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Affiliation(s)
- Sérgio Filipe Sousa
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal
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41
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Penner-Hahn J. Zinc-promoted alkyl transfer: a new role for zinc. Curr Opin Chem Biol 2007; 11:166-71. [PMID: 17376731 DOI: 10.1016/j.cbpa.2007.02.038] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Accepted: 02/20/2007] [Indexed: 10/23/2022]
Abstract
The roles of zinc in biology are often thought to be limited to activating water, as in hydrolytic enzymes, and conferring structure, as in the zinc finger proteins. Over the past 15 years, it has been shown that there are many zinc-containing proteins that have 'structural-like' zinc sites with multiple cysteine ligands but in which the site promotes the alkylation of a zinc-bound thiolate. Recent work continues to extend the range of proteins showing zinc-promoted alkytransfer activity, and has refined the structural details of these sites. Of particular interest are recent crystal structures suggesting that in most cases the endogenous ligand that is displaced when the substrate thiol bind is an endogenous amino acid and not water, as had been previously thought. Despite extensive study, it remains unclear whether these enzymes function via an associative mechanism (direct alkylation of a zinc-bound thiolate) or a dissociate mechanism (nucleophilic attack by a free thiolate that has dissociated from the zinc).
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Affiliation(s)
- James Penner-Hahn
- Department of Chemistry and Biophysics Research Division, University of Michigan, 930 North University Avenue, Ann Arbor, MI 48109-1055 USA.
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Sousa SF, Fernandes PA, Ramos MJ. The Carboxylate Shift in Zinc Enzymes: A Computational Study. J Am Chem Soc 2007; 129:1378-85. [PMID: 17263422 DOI: 10.1021/ja067103n] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Zinc is the second most abundant transition element in biology and the only metal known to be represented in enzymes from each one of the six classes established by the International Union of Biochemistry. The flexible coordination geometry, the fast ligand exchange, the lack of redox activity, and its role as Lewis acid are just some of the features that make zinc an invaluable element in biological catalysis. In this study, we have analyzed the importance in mononuclear Zn enzymes of an interesting mechanistic phenomenon known as carboxylate shift, which is characterized by a change in the coordination mode of a carboxylate group (mono to bidentate or vice versa) with both ligand entrance or exit from the metal coordination sphere. Using B3LYP calculations, we were able to unveil in detail patterns relating the intrinsic characteristics of a given Zn coordination sphere with the existence or not of a carboxylate-shift mechanism and the additional energy stabilization arising from it. In particular, a specific Zn coordination sphere containing a carboxylate ligand (Asp or Glu), a cysteine, and a histidine has been shown to have the most favorable combination of amino acid residues that ensures a fast ligand exchange.
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Affiliation(s)
- Sérgio F Sousa
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
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Sousa SF, Fernandes PA, Ramos MJ. Theoretical studies on farnesyl transferase: Evidence for thioether product coordination to the active-site zinc sphere. J Comput Chem 2007; 28:1160-8. [PMID: 17342704 DOI: 10.1002/jcc.20577] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Farnesyltransferase (FTase), an interesting zinc metaloenzyme, has been the subject of great attention in anticancer research over the last decade. However, despite the major accomplishments in the field, some very pungent questions on the farnesylation mechanism still persist. In this study, the authors have analyzed a mechanistic paradox that arises from the existence of several contradicting and inconclusive experimental evidence regarding the existence of direct coordination between the active-site zinc cation and the thioether from the farnesylated peptide product, which include UV-vis spectroscopy data on a Co(2+)-substituted FTase, two X-ray crystallographic structures of the FTase-product complex, and extended X-ray absorption fine structure results. Using high-level theoretical calculations on two models of different sizes, and QM/MM calculations on the full enzyme, the authors have shown that the farnesylated product is Zn coordinated, and that a subsequent step where this Zn bond is broken is coherent with the available kinetic results. Furthermore, an explanation for the contradicting experimental evidence is suggested.
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Affiliation(s)
- Sérgio Filipe Sousa
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
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Karlsson T, Skyllberg U. Complexation of zinc in organic soils--EXAFS evidence for sulfur associations. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2007; 41:119-24. [PMID: 17265936 DOI: 10.1021/es0608803] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Even if it is generally accepted that associations with natural organic matter (NOM) to a great extent determine the bioavailability and mobility of trace metals in soils and waters, the knowledge about the identity of NOM functional groups involved is still limited. In this study, extended X-ray absorption fine structure (EXAFS) spectroscopy was used to determine the coordination chemistry of zinc (Zn) in two organic soils (500-10,000 microg Zn g(-), pH 5.6-7.3). In both soils Zn was coordinated by a mixture of oxygen/nitrogen (O/N) and sulfur (S) ligands in the first coordination shell. In average, 0.4-0.9 S atoms were located at a distance of 2.29-2.33 angstom, well in agreement with a 4-fold coordination with thiolates (RS-) in proteins. In addition 2.7-3.7 O/N atoms were located at 1.99-2.04 angstrom. The improved merit of fit by inclusion of S atoms was shown to be significant after adjusting for the improvement caused merely by increasing the number of fitting parameters. Two second shell Zn-C distances were used in our model: 3.0-4.2 carbon (C) atoms, associated to first shell O/N, were encountered at an average distance of 2.84 amgstrom, and 0.4-0.9 C atoms, associated to first shell S, were encountered at an average distance of 3.32 angstrom. These Zn-C distances are well in agreement with distances determined in well-defined organic molecules. It is concluded that Zn forms mainly inner-sphere complexes with a mixture of 4-fold coordination with S and O/N ligands and 6-fold coordination with O ligands in organic soils.
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Affiliation(s)
- Torbjörn Karlsson
- Department of Forest Ecology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
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45
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Sousa SF, Fernandes PA, Ramos MJ. Theoretical studies on farnesyltransferase: The distances paradox explained. Proteins 2006; 66:205-18. [PMID: 17068802 DOI: 10.1002/prot.21219] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In spite of the enormous interest that has been devoted to its study, the mechanism of the enzyme farnesyltransferase (FTase) remains the subject of several crucial doubts. In this article, we shed a new light in one of the most fundamental dilemmas that characterize the mechanism of this puzzling enzyme commonly referred to as the "distances paradox", which arises from the existence of a large 8-A distance between the two reactive atoms in the reaction catalyzed by this enzyme: a Zn-bound cysteine sulphur atom from a peptidic substrate and the farnesyldiphosphate (FPP) carbon 1. This distance must be overcome for the reaction to occur. In this study, the two possible alternatives were evaluated by combining molecular mechanics (AMBER) and quantum chemical calculations (B3LYP). Basically, our results have shown that an activation of the Zn-bound cysteine thiolate with subsequent displacement from the zinc coordination sphere towards the FPP carbon 1 is not a realistic hypothesis of overcoming the large distance reported in the crystallographic structures of the ternary complexes between the two reactive atoms, but that a rotation involving the FPP molecule can bring the two atoms closer with moderate energetic cost, coherent with previous experimental data. This conclusion opens the door to an understanding of the chemical step in the farnesylation reaction.
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Affiliation(s)
- Sérgio Filipe Sousa
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal
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46
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Sousa SF, Fernandes PA, Ramos MJ. Effective tailor-made force field parameterization of the several Zn coordination environments in the puzzling FTase enzyme: opening the door to the full understanding of its elusive catalytic mechanism. Theor Chem Acc 2006. [DOI: 10.1007/s00214-006-0170-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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47
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Martínez CE, Bazilevskaya KA, Lanzirotti A. Zinc coordination to multiple ligand atoms in organic-rich surface soils. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2006; 40:5688-95. [PMID: 17007127 DOI: 10.1021/es0608343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We report on the solid-phase speciation of naturally occurring Zn in metalliferous organic-matter-rich surface soils. Synchrotron-based studies were used to probe elemental distribution and associations in soil particles (micro-XRF) together with the mineralogy (micro-XRD) and Zn bonding environment (Zn-micro-XANES) at the micrometer-scale level. The average bonding environment of Zn was also probed for bulk soils using XANES. We found the distribution of elements within soil particles to be heterogeneous; however, some elements are consistently co-located. While conventional XRD analyses of whole soils did not identify any Zn mineral phase, synchrotron-based-micro-XRD analyses indicated that sphalerite (ZnS) is present in a particle from a wetland soil (soil labeled G3). Linear combination fit (LCF) analyses of XANES spectra collected for bulk soils (Zn-XANES) and microm-regions (Zn-micro-XANES) within soil particles suggest Zn bonds to oxygen-, nitrogen-, and sulfur-functional groups in these sulfur-, nitrogen-, and zinc-rich organic surface soils. The XANES spectra of all bulk soils and of all microm-regions except for the wetland soil (G3), where ZnS was the most significant constituent, were best fitted by the Zn-arginine reference compound and therefore seems to indicate Zn bonding to nitrogen. Thus, these results provide compelling evidence of the formation of highly covalent Zn-organic bonds in the organic-rich surface soils that were studied. This may explain in part why metal partition coefficients (Kd) are generally higher in organic soils, and why the toxic thresholds for total metal concentrations are higher in organic than in mineral soils.
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Affiliation(s)
- Carmen Enid Martínez
- Department of Crop and Soil Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA.
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48
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Lane KT, Beese LS. Thematic review series: lipid posttranslational modifications. Structural biology of protein farnesyltransferase and geranylgeranyltransferase type I. J Lipid Res 2006; 47:681-99. [PMID: 16477080 DOI: 10.1194/jlr.r600002-jlr200] [Citation(s) in RCA: 197] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
More than 100 proteins necessary for eukaryotic cell growth, differentiation, and morphology require posttranslational modification by the covalent attachment of an isoprenoid lipid (prenylation). Prenylated proteins include members of the Ras, Rab, and Rho families, lamins, CENPE and CENPF, and the gamma subunit of many small heterotrimeric G proteins. This modification is catalyzed by the protein prenyltransferases: protein farnesyltransferase (FTase), protein geranylgeranyltransferase type I (GGTase-I), and GGTase-II (or RabGGTase). In this review, we examine the structural biology of FTase and GGTase-I (the CaaX prenyltransferases) to establish a framework for understanding the molecular basis of substrate specificity and mechanism. These enzymes have been identified in a number of species, including mammals, fungi, plants, and protists. Prenyltransferase structures include complexes that represent the major steps along the reaction path, as well as a number of complexes with clinically relevant inhibitors. Such complexes may assist in the design of inhibitors that could lead to treatments for cancer, viral infection, and a number of deadly parasitic diseases.
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Affiliation(s)
- Kimberly T Lane
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
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49
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Matsunaga Y, Fujisawa K, Ibi N, Fujita M, Ohashi T, Amir N, Miyashita Y, Aika KI, Izumi Y, Okamoto KI. Sulfur K-edge extended X-ray absorption fine structure spectroscopy of homoleptic thiolato complexes with Zn(II) and Cd(II). J Inorg Biochem 2006; 100:239-49. [PMID: 16387363 DOI: 10.1016/j.jinorgbio.2005.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2005] [Revised: 11/06/2005] [Accepted: 11/09/2005] [Indexed: 11/30/2022]
Abstract
The sulfur K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy is applied to homoleptic thiolato complexes with Zn(II) and Cd(II), (Et(4)N)[Zn(SAd)(3)] (1), (Et(4)N)(2)[{Zn(ScHex)(2)}(2)(mu-ScHex)(2)] (2), (Et(4)N)(2)[{Cd(ScHex)(2)}(2)(mu-ScHex)(2)] (3), (Et(4)N)(2)[{Cd(ScHex)}(4)(mu-ScHex)(6)] (4), [Zn(mu-SAd)(2)](n) (5), and [Cd(mu-SAd)(2)](n) (6) (HSAd=1-adamantanethiol, HScHex=cyclohexanethiol). The EXAFS results are consistent with the X-ray crystal data of 1-4. The structures of 5 and 6, which have not been determined by X-ray crystallography, are proposed to be polynuclear structures on the basis of the sulfur K-edge EXAFS, far-IR spectra, and elemental analysis. Clear evidences of the S...S interactions (between bridging atoms or neighboring sulfur atoms) and the S...C(far) interactions (in which C(far) atom is next to carbon atom directly bonded to sulfur atom) were observed in the EXAFS data for all complexes and thus lead to the reliable determination of the structures of 5 and 6 in combination with conventional zinc K-edge EXAFS analysis for 5. This new methodology, sulfur K-edge EXAFS, could be applied for the structural determination of in vivo metalloproteins as well as inorganic compounds.
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Affiliation(s)
- Yuki Matsunaga
- Graduate School of Pure and Applied Sciences, Department of Chemistry, University of Tsukuba, Tsukuba 305-8571, Japan
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Hernick M, Fierke CA. Zinc hydrolases: the mechanisms of zinc-dependent deacetylases. Arch Biochem Biophys 2005; 433:71-84. [PMID: 15581567 DOI: 10.1016/j.abb.2004.08.006] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Revised: 08/04/2004] [Indexed: 11/17/2022]
Abstract
A class of metalloenzymes, known as zinc hydrolases, catalyze a variety of hydrolytic reactions on many different substrates in important metabolic pathways. Deacetylation is an example of one of the types of reactions catalyzed by zinc hydrolases. The biological importance of the reactions catalyzed by many zinc hydrolases, including zinc-dependent deacetylases, has made these enzymes pharmaceutical targets for the development of inhibitors and, therefore, a clear understanding of the mechanisms of these enzymes is warranted. This review focuses on the current understanding of the mechanisms catalyzed by various zinc-dependent deacetylases and, in particular, the reaction mechanism catalyzed by the enzyme UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase, also known as LpxC. In general, the zinc-water functions as the nucleophile with zinc stabilization of the tetrahedral intermediate and general-acid-base catalysis (GABC) provided by enzyme residue(s). Two types of GABC mechanisms have been identified, one that uses a single bifunctional GABC and another that uses a GABC pair.
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Affiliation(s)
- Marcy Hernick
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
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