1
|
Yang J, Mintmier B, Kc K, Metzger MC, Radhakrishnan M, McGarry J, Wilcoxen J, Basu P, Kirk ML. Active Site Characterization of a Campylobacter jejuni Nitrate Reductase Variant Provides Insight into the Enzyme Mechanism. Inorg Chem 2024; 63:13191-13196. [PMID: 38984973 DOI: 10.1021/acs.inorgchem.4c01991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
Mo K-edge X-ray absorption spectroscopy (XAS) is used to probe the structure of wild-type Campylobacter jejuni nitrate reductase NapA and the C176A variant. The results of extended X-ray absorption fine structure (EXAFS) experiments on wt NapA support an oxidized Mo(VI) hexacoordinate active site coordinated by a single terminal oxo donor, four sulfur atoms from two separate pyranopterin dithiolene ligands, and an additional S atom from a conserved cysteine amino acid residue. We found no evidence of a terminal sulfido ligand in wt NapA. EXAFS analysis shows the C176A active site to be a 6-coordinate structure, and this is supported by EPR studies on C176A and small molecule analogs of Mo(V) enzyme forms. The SCys is replaced by a hydroxide or water ligand in C176A, and we find no evidence of a coordinated sulfhydryl (SH) ligand. Kinetic studies show that this variant has completely lost its catalytic activity toward nitrate. Taken together, the results support a critical role for the conserved C176 in catalysis and an oxygen atom transfer mechanism for the catalytic reduction of nitrate to nitrite that does not employ a terminal sulfido ligand in the catalytic cycle.
Collapse
Affiliation(s)
- Jing Yang
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - Breeanna Mintmier
- Department of Chemistry and Chemical Biology, Indiana University, 402 Blackford St., Indianapolis, Indiana 46202, United States
| | - Khadanand Kc
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - Mikayla C Metzger
- Department of Chemistry and Chemical Biology, Indiana University, 402 Blackford St., Indianapolis, Indiana 46202, United States
| | - Manohar Radhakrishnan
- Department of Chemistry and Chemical Biology, Indiana University, 402 Blackford St., Indianapolis, Indiana 46202, United States
| | - Jennifer McGarry
- Department of Chemistry and Chemical Biology, Indiana University, 402 Blackford St., Indianapolis, Indiana 46202, United States
- Department of Chemistry and Biochemistry, University of Wisconsin, 3210 N. Cramer St., Milwaukee, Wisconsin 53211, United States
| | - Jarett Wilcoxen
- Department of Chemistry and Biochemistry, University of Wisconsin, 3210 N. Cramer St., Milwaukee, Wisconsin 53211, United States
| | - Partha Basu
- Department of Chemistry and Chemical Biology, Indiana University, 402 Blackford St., Indianapolis, Indiana 46202, United States
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| |
Collapse
|
2
|
Burgmayer SJN, Kirk ML. Advancing Our Understanding of Pyranopterin-Dithiolene Contributions to Moco Enzyme Catalysis. Molecules 2023; 28:7456. [PMID: 38005178 PMCID: PMC10673323 DOI: 10.3390/molecules28227456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 11/26/2023] Open
Abstract
The pyranopterin dithiolene ligand is remarkable in terms of its geometric and electronic structure and is uniquely found in mononuclear molybdenum and tungsten enzymes. The pyranopterin dithiolene is found coordinated to the metal ion, deeply buried within the protein, and non-covalently attached to the protein via an extensive hydrogen bonding network that is enzyme-specific. However, the function of pyranopterin dithiolene in enzymatic catalysis has been difficult to determine. This focused account aims to provide an overview of what has been learned from the study of pyranopterin dithiolene model complexes of molybdenum and how these results relate to the enzyme systems. This work begins with a summary of what is known about the pyranopterin dithiolene ligand in the enzymes. We then introduce the development of inorganic small molecule complexes that model aspects of a coordinated pyranopterin dithiolene and discuss the results of detailed physical studies of the models by electronic absorption, resonance Raman, X-ray absorption and NMR spectroscopies, cyclic voltammetry, X-ray crystallography, and chemical reactivity.
Collapse
Affiliation(s)
| | - Martin L. Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, NM 87131, USA
| |
Collapse
|
3
|
Struwe MA, Scheidig AJ, Clement B. The mitochondrial amidoxime reducing component-from prodrug-activation mechanism to drug-metabolizing enzyme and onward to drug target. J Biol Chem 2023; 299:105306. [PMID: 37778733 PMCID: PMC10637980 DOI: 10.1016/j.jbc.2023.105306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 09/17/2023] [Accepted: 09/24/2023] [Indexed: 10/03/2023] Open
Abstract
The mitochondrial amidoxime-reducing component (mARC) is one of five known molybdenum enzymes in eukaryotes. mARC belongs to the MOSC domain superfamily, a large group of so far poorly studied molybdoenzymes. mARC was initially discovered as the enzyme activating N-hydroxylated prodrugs of basic amidines but has since been shown to also reduce a variety of other N-oxygenated compounds, for example, toxic nucleobase analogs. Under certain circumstances, mARC might also be involved in reductive nitric oxide synthesis through reduction of nitrite. Recently, mARC enzymes have received a lot of attention due to their apparent involvement in lipid metabolism and, in particular, because many genome-wide association studies have shown a common variant of human mARC1 to have a protective effect against liver disease. The mechanism linking mARC enzymes with lipid metabolism remains unknown. Here, we give a comprehensive overview of what is currently known about mARC enzymes, their substrates, structure, and apparent involvement in human disease.
Collapse
Affiliation(s)
- Michel A Struwe
- Zoologisches Institut - Strukturbiologie, Christian-Albrechts-Universität Kiel, Kiel, Germany; Pharmazeutisches Institut, Christian-Albrechts-Universität Kiel, Kiel, Germany.
| | - Axel J Scheidig
- Zoologisches Institut - Strukturbiologie, Christian-Albrechts-Universität Kiel, Kiel, Germany
| | - Bernd Clement
- Pharmazeutisches Institut, Christian-Albrechts-Universität Kiel, Kiel, Germany
| |
Collapse
|
4
|
Enemark JH. Mechanistic complexities of sulfite oxidase: An enzyme with multiple domains, subunits, and cofactors. J Inorg Biochem 2023; 247:112312. [PMID: 37441922 DOI: 10.1016/j.jinorgbio.2023.112312] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/13/2023] [Accepted: 07/01/2023] [Indexed: 07/15/2023]
Abstract
Sulfite oxidase (SO) deficiency, an inherited disease that causes severe neonatal neurological problems and early death, arises from defects in the biosynthesis of the molybdenum cofactor (Moco) (general sulfite oxidase deficiency) or from inborn errors in the SUOX gene for SO (isolated sulfite oxidase deficiency, ISOD). The X-ray structure of the highly homologous homonuclear dimeric chicken sulfite oxidase (cSO) provides a template for locating ISOD mutation sites in human sulfite oxidase (hSO). Catalysis occurs within an individual subunit of hSO, but mutations that disrupt the hSO dimer are pathological. The catalytic cycle of SO involves five metal oxidation states (MoVI, MoV, MoIV, FeIII, FeII), two intramolecular electron transfer (IET) steps, and couples a two-electron oxygen atom transfer reaction at the Mo center with two one-electron transfers from the integral b-type heme to exogenous cytochrome c, the physiological oxidant. Several ISOD examples are analyzed using steady-state, stopped-flow, and laser flash photolysis kinetics and physical measurements of recombinant variants of hSO and native cSO. In the structure of cSO, Mo…Fe = 32 Å, much too long for efficient IET through the protein. Interdomain motion that brings the Mo and heme centers closer together to facilitate IET is supported indirectly by decreasing the length of the interdomain tether, by changes in the charges of surface residues of the Mo and heme domains, as well as by preliminary molecular dynamics calculations. However, direct dynamic measurements of interdomain motion are in their infancy.
Collapse
Affiliation(s)
- John H Enemark
- Department of Chemistry and Biochemistry, The University of Arizona, 1306 East University Blvd, Tucson, AZ 85721-0041, United States of America.
| |
Collapse
|
5
|
Winiarska A, Ramírez-Amador F, Hege D, Gemmecker Y, Prinz S, Hochberg G, Heider J, Szaleniec M, Schuller JM. A bacterial tungsten-containing aldehyde oxidoreductase forms an enzymatic decorated protein nanowire. SCIENCE ADVANCES 2023; 9:eadg6689. [PMID: 37267359 PMCID: PMC10413684 DOI: 10.1126/sciadv.adg6689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 04/28/2023] [Indexed: 06/04/2023]
Abstract
Aldehyde oxidoreductases (AORs) are tungsten enzymes catalyzing the oxidation of many different aldehydes to the corresponding carboxylic acids. In contrast to other known AORs, the enzyme from the denitrifying betaproteobacterium Aromatoleum aromaticum (AORAa) consists of three different subunits (AorABC) and uses nicotinamide adenine dinucleotide (NAD) as an electron acceptor. Here, we reveal that the enzyme forms filaments of repeating AorAB protomers that are capped by a single NAD-binding AorC subunit, based on solving its structure via cryo-electron microscopy. The polyferredoxin-like subunit AorA oligomerizes to an electron-conducting nanowire that is decorated with enzymatically active and W-cofactor (W-co) containing AorB subunits. Our structure further reveals the binding mode of the native substrate benzoate in the AorB active site. This, together with quantum mechanics:molecular mechanics (QM:MM)-based modeling for the coordination of the W-co, enables formulation of a hypothetical catalytic mechanism that paves the way to further engineering for applications in synthetic biology and biotechnology.
Collapse
Affiliation(s)
- Agnieszka Winiarska
- Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences, Kraków, Poland
| | - Fidel Ramírez-Amador
- SYNMIKRO Research Center and Department of Chemistry, Philipps-University of Marburg, Marburg, Germany
| | - Dominik Hege
- Faculty of Biology, Philipps-University of Marburg, Marburg, Germany
| | - Yvonne Gemmecker
- Faculty of Biology, Philipps-University of Marburg, Marburg, Germany
| | - Simone Prinz
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Georg Hochberg
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Johann Heider
- SYNMIKRO Research Center and Department of Chemistry, Philipps-University of Marburg, Marburg, Germany
- Faculty of Biology, Philipps-University of Marburg, Marburg, Germany
| | - Maciej Szaleniec
- Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences, Kraków, Poland
| | - Jan Michael Schuller
- SYNMIKRO Research Center and Department of Chemistry, Philipps-University of Marburg, Marburg, Germany
| |
Collapse
|
6
|
Kirk ML, Lepluart J, Yang J. Resonance Raman spectroscopy of pyranopterin molybdenum enzymes. J Inorg Biochem 2022; 235:111907. [PMID: 35932756 PMCID: PMC10575615 DOI: 10.1016/j.jinorgbio.2022.111907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 05/16/2022] [Accepted: 06/16/2022] [Indexed: 10/17/2022]
Abstract
Resonance Raman spectroscopy (rR) is a powerful spectroscopic probe that is widely used for studying the geometric and electronic structure of metalloproteins. In this focused review, we detail how resonance Raman spectroscopy has contributed to a greater understanding of electronic structure, geometric structure, and the reaction mechanisms of pyranopterin molybdenum enzymes. The review focuses on the enzymes sulfite oxidase (SO), dimethyl sulfoxide reductase (DMSOR), xanthine oxidase (XO), and carbon monoxide dehydrogenase. Specifically, we highlight how Mo-Ooxo, Mo-Ssulfido, Mo-Sdithiolene, and dithiolene CC vibrational modes, isotope and heavy atom perturbations, resonance enhancement, and associated Raman studies of small molecule analogs have provided detailed insight into the nature of these metalloenzyme active sites.
Collapse
Affiliation(s)
- Martin L Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001, United States.
| | - Jesse Lepluart
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001, United States
| | - Jing Yang
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001, United States
| |
Collapse
|
7
|
Gates C, Varnum H, Getty C, Loui N, Chen J, Kirk ML, Yang J, Nieter Burgmayer SJ. Protonation and Non-Innocent Ligand Behavior in Pyranopterin Dithiolene Molybdenum Complexes. Inorg Chem 2022; 61:13728-13742. [PMID: 36000991 PMCID: PMC10544801 DOI: 10.1021/acs.inorgchem.2c01234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The complex [TEA][Tp*MoIV(O)(S2BMOPP)] (1) [TEA = tetraethylammonium, Tp* = tris(3,5-dimethylpyrazolyl)hydroborate, and BMOPP = 6-(3-butynyl-2-methyl-2-ol)-2-pivaloyl pterin] is a structural analogue of the molybdenum cofactor common to all pyranopterin molybdenum enzymes because it possesses a pyranopterin-ene-1,2-dithiolate ligand (S2BMOPP) that exists primarily in the ring-closed pyrano structure as a resonance hybrid of ene-dithiolate and thione-thiolate forms. Compound 1, the protonated [Tp*MoIV(O)(S2BMOPP-H)] (1-H) and one-electron-oxidized [Tp*MoV(O)(S2BMOPP)] [1-Mo(5+)] species have been studied using a combination of electrochemistry, electronic absorption, and electron paramagnetic resonance (EPR) spectroscopy. Additional insight into the nature of these molecules has been derived from electronic structure computations. Differences in dithiolene C-S bond lengths correlate with relative contributions from both ene-dithiolate and thione-thiolate resonance structures. Upon protonation of 1 to form 1-H, large spectroscopic changes are observed with transitions assigned as Mo(xy) → pyranopterin metal-to-ligand charge transfer and dithiolene → pyranopterin intraligand charge transfer, respectively, and this underscores a dramatic change in electronic structure between 1 and 1-H. The changes in electronic structure that occur upon protonation of 1 are also reflected in a large >300 mV increase in the Mo(V/IV) redox potential for 1-H, resulting from the greater thione-thiolate resonance contribution and decreased charge donation that stabilize the Mo(IV) state in 1-H with respect to one-electron oxidation. EPR spin Hamiltonian parameters for one-electron-oxidized 1-Mo(5+) and uncyclized [Tp*MoV(O)(S2BDMPP)] [3-Mo(5+)] [BDMPP = 6-(3-butynyl-2,2-dimethyl)-2-pivaloyl pterin] are very similar to each other and to those of [Tp*MoVO(bdt)] (bdt = 1,2-ene-dithiolate). This indicates that the dithiolate form of the ligand dominates at the Mo(V) level, consistent with the demand for greater S → Mo charge donation and a corresponding increase in Mo-S covalency as the oxidation state of the metal is increased. Protonation of 1 represents a simple reaction that models how the transfer of a proton from neighboring acidic amino acid residues to the Mo cofactor at a nitrogen atom within the pyranopterin dithiolene (PDT) ligand in pyranopterin molybdenum enzymes can impact the electronic structure of the Mo-PDT unit. This work also illustrates how pyran ring-chain tautomerization drives changes in resonance contributions to the dithiolene chelate and may adjust the reduction potential of the Mo ion.
Collapse
Affiliation(s)
- Cassandra Gates
- Department of Chemistry, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010, United States
| | - Haley Varnum
- Department of Chemistry, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010, United States
| | - Catherine Getty
- Department of Chemistry, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010, United States
| | - Natalie Loui
- Department of Chemistry, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010, United States
| | - Ju Chen
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - Jing Yang
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | | |
Collapse
|
8
|
Kirk ML, Hille R. Spectroscopic Studies of Mononuclear Molybdenum Enzyme Centers. Molecules 2022; 27:molecules27154802. [PMID: 35956757 PMCID: PMC9370002 DOI: 10.3390/molecules27154802] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/26/2022] [Accepted: 06/29/2022] [Indexed: 02/06/2023] Open
Abstract
A concise review is provided of the contributions that various spectroscopic methods have made to our understanding of the physical and electronic structures of mononuclear molybdenum enzymes. Contributions to our understanding of the structure and function of each of the major families of these enzymes is considered, providing a perspective on how spectroscopy has impacted the field.
Collapse
Affiliation(s)
- Martin L. Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001, USA
- Correspondence: (M.L.K.); (R.H.)
| | - Russ Hille
- Department of Biochemistry, Boyce Hall 1463, University of California, Riverside, CA 82521, USA
- Correspondence: (M.L.K.); (R.H.)
| |
Collapse
|
9
|
Tiedemann K, Iobbi-Nivol C, Leimkühler S. The Role of the Nucleotides in the Insertion of the bis-Molybdopterin Guanine Dinucleotide Cofactor into apo-Molybdoenzymes. Molecules 2022; 27:molecules27092993. [PMID: 35566344 PMCID: PMC9103625 DOI: 10.3390/molecules27092993] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 04/15/2022] [Accepted: 04/29/2022] [Indexed: 02/04/2023] Open
Abstract
The role of the GMP nucleotides of the bis-molybdopterin guanine dinucleotide (bis-MGD) cofactor of the DMSO reductase family has long been a subject of discussion. The recent characterization of the bis-molybdopterin (bis-Mo-MPT) cofactor present in the E. coli YdhV protein, which differs from bis-MGD solely by the absence of the nucleotides, now enables studying the role of the nucleotides of bis-MGD and bis-MPT cofactors in Moco insertion and the activity of molybdoenzymes in direct comparison. Using the well-known E. coli TMAO reductase TorA as a model enzyme for cofactor insertion, we were able to show that the GMP nucleotides of bis-MGD are crucial for the insertion of the bis-MGD cofactor into apo-TorA.
Collapse
Affiliation(s)
- Kim Tiedemann
- Institute of Biochemistry and Biology, Molecular Enzymology, University of Potsdam, Karl-Liebknecht Str. 24-25, 14476 Potsdam-Golm, Germany;
| | - Chantal Iobbi-Nivol
- Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Centre National de la Recherche Scientifique, Aix-Marseille Université, CEDEX 09, 13402 Marseille, France;
| | - Silke Leimkühler
- Institute of Biochemistry and Biology, Molecular Enzymology, University of Potsdam, Karl-Liebknecht Str. 24-25, 14476 Potsdam-Golm, Germany;
- Correspondence:
| |
Collapse
|
10
|
Ha Y, Dille SA, Braun A, Colston K, Hedman B, Hodgson KO, Basu P, Solomon EI. S K-edge XAS of Cu II, Cu I, and Zn II oxidized Dithiolene complexes: Covalent contributions to structure and the Jahn-Teller effect. J Inorg Biochem 2022; 230:111752. [PMID: 35202982 PMCID: PMC9680909 DOI: 10.1016/j.jinorgbio.2022.111752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/01/2022] [Accepted: 02/03/2022] [Indexed: 11/26/2022]
Abstract
Reduced dithiolene ligands are bound to high valent Mo centers in the active site of the oxotransferase family of enzymes. Related model complexes have been studied with great insight by Prof. Holm and his colleagues. This study focuses on the other limit of dithiolene chemistry: an investigation of the 2-electron oxidized dithiolene bound to low-valent late transition metal (TM) ions (ZnII, CuI, and CuII). The bonding descriptions of the oxidized dithiolene [N,N-dimethyl piperazine 2,3-dithione (Me2Dt0)] complexes are probed using S K-edge X-ray absorption spectroscopy (XAS) and the results are correlated to density functional theory (DFT) calculations. These experimentally supported calculations are then extended to explain the different geometric structures of the three complexes. The ZnII(Me2Dt0)2 complex has only ligand-ligand repulsion so it is stabilized at the D2d symmetry limit. The CuI(Me2Dt0)2 complex has additional weak backbonding thus distorts somewhat from D2d toward D2h symmetry. The CuII(Me2Dt0)2 complex has a strong σ donor bond that leads to both a large Jahn-Teller stabilization to D2h and an additional covalent contribution to the geometry. The combined strong stabilization results in the square planar, D2h structure. This study quantifies the competition between the ligand-ligand repulsion and the change in electronic structures in determining the final geometric structures of the oxidized dithiolene complexes, and provides quantitative insights into the Jahn-Teller stabilization energy and its origin.
Collapse
Affiliation(s)
- Yang Ha
- Department of Chemistry, Stanford University, Stanford, CA 94035, United States; Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, United States; Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, United States
| | - Sara A Dille
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, 402 N Blackford St, Indianapolis, IN 46202, United States
| | - Augustin Braun
- Department of Chemistry, Stanford University, Stanford, CA 94035, United States; Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, United States
| | - Kyle Colston
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, 402 N Blackford St, Indianapolis, IN 46202, United States
| | - Britt Hedman
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, United States
| | - Keith O Hodgson
- Department of Chemistry, Stanford University, Stanford, CA 94035, United States; Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, United States
| | - Partha Basu
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, 402 N Blackford St, Indianapolis, IN 46202, United States
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, CA 94035, United States; Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, United States.
| |
Collapse
|
11
|
Enemark JH. {Moco}n, (n = 0–8): A general formalism for describing the highly covalent molybdenum cofactor of sulfite oxidase and related Mo enzymes,. J Inorg Biochem 2022; 231:111801. [DOI: 10.1016/j.jinorgbio.2022.111801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 03/05/2022] [Accepted: 03/13/2022] [Indexed: 11/29/2022]
|
12
|
Le CC, Bae M, Kiamehr S, Balskus EP. Emerging Chemical Diversity and Potential Applications of Enzymes in the DMSO Reductase Superfamily. Annu Rev Biochem 2022; 91:475-504. [PMID: 35320685 DOI: 10.1146/annurev-biochem-032620-110804] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Molybdenum- and tungsten-dependent proteins catalyze essential processes in living organisms and biogeochemical cycles. Among these enzymes, members of the dimethyl sulfoxide (DMSO) reductase superfamily are considered the most diverse, facilitating a wide range of chemical transformations that can be categorized as oxygen atom installation, removal, and transfer. Importantly, DMSO reductase enzymes provide high efficiency and excellent selectivity while operating under mild conditions without conventional oxidants such as oxygen or peroxides. Despite the potential utility of these enzymes as biocatalysts, such applications have not been fully explored. In addition, the vast majority of DMSO reductase enzymes still remain uncharacterized. In this review, we describe the reactivities, proposed mechanisms, and potential synthetic applications of selected enzymes in the DMSO reductase superfamily. We also highlight emerging opportunities to discover new chemical activity and current challenges in studying and engineering proteins in the DMSO reductase superfamily. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Chi Chip Le
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA;
| | - Minwoo Bae
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA;
| | - Sina Kiamehr
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA;
| | - Emily P Balskus
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA;
| |
Collapse
|
13
|
González PJ, Rivas MG, Ferroni FM, Rizzi AC, Brondino CD. Electron transfer pathways and spin–spin interactions in Mo- and Cu-containing oxidoreductases. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
14
|
Dille SA, Colston KJ, Ratvasky SC, Pu J, Basu P. Interligand communication in a metal mediated LL'CT system - a case study. RSC Adv 2021; 11:24381-24386. [PMID: 34354823 PMCID: PMC8285364 DOI: 10.1039/d1ra04716g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 07/06/2021] [Indexed: 11/22/2022] Open
Abstract
A series of oxo-Mo(iv) complexes, [MoO(Dt2−)(Dt0)] (where Dt2− = benzene-1,2-dithiol (bdt), toluene-3,4-dithiol (tdt), quinoxaline-2,3-dithiol (qdt), or 3,6-dichloro-benzene-1,2-dithiol (bdtCl2); Dt0 = N,N′-dimethylpiperazine-2,3-dithione (Me2Dt0) or N,N′-diisopropylpiperazine-2,3-dithione (iPr2Dt0)), possessing a fully oxidized and a fully reduced dithiolene ligand have been synthesized and characterized. The assigned oxidation states of coordinated dithiolene ligands are supported with spectral and crystallographic data. The molecular structure of [MoO(tdt)(iPr2Dt0)] (6) demonstrates a large ligand fold angle of 62.6° along the S⋯S vector of the Dt0 ligand. The electronic structure of this system is probed by density functional theory (DFT) calculations. The HOMO is largely localized on the Dt2− ligand while virtual orbitals are mostly Mo and Dt0 in character. Modeling the electronic spectrum of 6 with time dependent (TD) DFT calculations attributes the intense low energy transition at ∼18 000 cm−1 to a ligand-to-ligand charge transfer (LL′CT). The electron density difference map (EDDM) for the low energy transition depicts the electron rich Dt2− ligand donating charge density to the redox-active orbitals of the electron deficient Dt0 ligand. Electronic communication between dithiolene ligands is facilitated by a Mo-monooxo center and distortion about its primary coordination sphere. The interligand communication between non-innocent dithiolene ligands of different oxidation states has been described in a Mo system. The fully reduced ene-dithiolate (Dt2−) acts as a donor moiety to the oxidized dithione (Dt0) in an LL′CT process.![]()
Collapse
Affiliation(s)
- Sara A Dille
- Department of Chemistry and Chemical Biology, Indiana University - Purdue University Indianapolis Indianapolis IN 46202 USA
| | - Kyle J Colston
- Department of Chemistry and Chemical Biology, Indiana University - Purdue University Indianapolis Indianapolis IN 46202 USA
| | - Stephen C Ratvasky
- Department of Chemistry and Biochemistry, Duquesne University Pittsburgh PA 15282 USA
| | - Jingzhi Pu
- Department of Chemistry and Chemical Biology, Indiana University - Purdue University Indianapolis Indianapolis IN 46202 USA
| | - Partha Basu
- Department of Chemistry and Chemical Biology, Indiana University - Purdue University Indianapolis Indianapolis IN 46202 USA
| |
Collapse
|
15
|
Probst C, Yang J, Krausze J, Hercher TW, Richers CP, Spatzal T, Kc K, Giles LJ, Rees DC, Mendel RR, Kirk ML, Kruse T. Mechanism of molybdate insertion into pterin-based molybdenum cofactors. Nat Chem 2021; 13:758-765. [PMID: 34183818 PMCID: PMC8325642 DOI: 10.1038/s41557-021-00714-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 04/27/2021] [Indexed: 02/06/2023]
Abstract
The molybdenum cofactor (Moco) is found in the active site of numerous important enzymes that are critical to biological processes. The bidentate ligand that chelates molybdenum in Moco is the pyranopterin dithiolene (molybdopterin, MPT). However, neither the mechanism of molybdate insertion into MPT nor the structure of Moco prior to its insertion into pyranopterin molybdenum enzymes is known. Here, we report this final maturation step, where adenylated MPT (MPT-AMP) and molybdate are the substrates. X-ray crystallography of the Arabidopsis thaliana Mo-insertase variant Cnx1E S269D D274S identified adenylated Moco (Moco-AMP) as an unexpected intermediate in this reaction sequence. X-ray absorption spectroscopy revealed the first coordination sphere geometry of Moco trapped in the Cnx1E active site. We have used this structural information to deduce a mechanism for molybdate insertion into MPT-AMP. Given their high degree of structural and sequence similarity, we suggest that this mechanism is employed by all eukaryotic Mo-insertases.
Collapse
Affiliation(s)
- Corinna Probst
- Institute of Plant Biology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Jing Yang
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, NM, USA
| | - Joern Krausze
- Institute of Plant Biology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Thomas W Hercher
- Institute of Plant Biology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Casseday P Richers
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, NM, USA
| | - Thomas Spatzal
- Division of Chemistry and Chemical Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, USA
| | - Khadanand Kc
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, NM, USA
| | - Logan J Giles
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, NM, USA
| | - Douglas C Rees
- Division of Chemistry and Chemical Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, USA
| | - Ralf R Mendel
- Institute of Plant Biology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, NM, USA.
| | - Tobias Kruse
- Institute of Plant Biology, Technische Universität Braunschweig, Braunschweig, Germany.
| |
Collapse
|
16
|
Struwe MA, Kalimuthu P, Luo Z, Zhong Q, Ellis D, Yang J, Khadanand KC, Harmer JR, Kirk ML, McEwan AG, Clement B, Bernhardt PV, Kobe B, Kappler U. Active site architecture reveals coordination sphere flexibility and specificity determinants in a group of closely related molybdoenzymes. J Biol Chem 2021; 296:100672. [PMID: 33887324 PMCID: PMC8166771 DOI: 10.1016/j.jbc.2021.100672] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 04/11/2021] [Accepted: 04/14/2021] [Indexed: 11/27/2022] Open
Abstract
MtsZ is a molybdenum-containing methionine sulfoxide reductase that supports virulence in the human respiratory pathogen Haemophilus influenzae (Hi). HiMtsZ belongs to a group of structurally and spectroscopically uncharacterized S-/N-oxide reductases, all of which are found in bacterial pathogens. Here, we have solved the crystal structure of HiMtsZ, which reveals that the HiMtsZ substrate-binding site encompasses a previously unrecognized part that accommodates the methionine sulfoxide side chain via interaction with His182 and Arg166. Charge and amino acid composition of this side chain–binding region vary and, as indicated by electrochemical, kinetic, and docking studies, could explain the diverse substrate specificity seen in closely related enzymes of this type. The HiMtsZ Mo active site has an underlying structural flexibility, where dissociation of the central Ser187 ligand affected catalysis at low pH. Unexpectedly, the two main HiMtsZ electron paramagnetic resonance (EPR) species resembled not only a related dimethyl sulfoxide reductase but also a structurally unrelated nitrate reductase that possesses an Asp–Mo ligand. This suggests that contrary to current views, the geometry of the Mo center and its primary ligands, rather than the specific amino acid environment, is the main determinant of the EPR properties of mononuclear Mo enzymes. The flexibility in the electronic structure of the Mo centers is also apparent in two of three HiMtsZ EPR-active Mo(V) species being catalytically incompetent off-pathway forms that could not be fully oxidized.
Collapse
Affiliation(s)
- Michel A Struwe
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia; Pharmazeutisches Institut, Christian-Albrechts-Universität Kiel, Kiel, Germany
| | - Palraj Kalimuthu
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia
| | - Zhenyao Luo
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia; Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, Australia
| | - Qifeng Zhong
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia
| | - Daniel Ellis
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia
| | - Jing Yang
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico, USA
| | - K C Khadanand
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico, USA
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, The University of Queensland, Brisbane, Qld, Australia
| | - Martin L Kirk
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, Australia
| | - Alastair G McEwan
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia
| | - Bernd Clement
- Pharmazeutisches Institut, Christian-Albrechts-Universität Kiel, Kiel, Germany
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia
| | - Bostjan Kobe
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia; Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, Australia
| | - Ulrike Kappler
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia.
| |
Collapse
|
17
|
Aiding a Better Understanding of Molybdopterin: Syntheses, Structures, and pKa Value Determinations of Varied Pterin-Derived Organic Scaffolds Including Oxygen, Sulfur and Phosphorus Bearing Substituents. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2020.129867] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
18
|
Radon C, Mittelstädt G, Duffus BR, Bürger J, Hartmann T, Mielke T, Teutloff C, Leimkühler S, Wendler P. Cryo-EM structures reveal intricate Fe-S cluster arrangement and charging in Rhodobacter capsulatus formate dehydrogenase. Nat Commun 2020; 11:1912. [PMID: 32313256 PMCID: PMC7171172 DOI: 10.1038/s41467-020-15614-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/19/2020] [Indexed: 11/09/2022] Open
Abstract
Metal-containing formate dehydrogenases (FDH) catalyse the reversible oxidation of formate to carbon dioxide at their molybdenum or tungsten active site. They display a diverse subunit and cofactor composition, but structural information on these enzymes is limited. Here we report the cryo-electron microscopic structures of the soluble Rhodobacter capsulatus FDH (RcFDH) as isolated and in the presence of reduced nicotinamide adenine dinucleotide (NADH). RcFDH assembles into a 360 kDa dimer of heterotetramers revealing a putative interconnection of electron pathway chains. In the presence of NADH, the RcFDH structure shows charging of cofactors, indicative of an increased electron load. Rhodobacter capsulatus NAD+ dependent formate dehydrogenase (RcFDH) is a molybdoenzyme that catalyses the reversible oxidation of formate to carbon dioxide, and is of interest for biotechnological applications. Here the authors present the cryo-EM structures of RcFDH as isolated from R. capsulatus and in the reduced state with bound NADH, and discuss the enzyme mechanism.
Collapse
Affiliation(s)
- Christin Radon
- Institute of Biochemistry and Biology, Department of Biochemistry, University of Potsdam, Karl-Liebknecht Strasse 24-25, 14476, Potsdam-Golm, Germany
| | - Gerd Mittelstädt
- Institute of Biochemistry and Biology, Department of Molecular Enzymology, University of Potsdam, Karl-Liebknecht Strasse 24-25, 14476, Potsdam-Golm, Germany.,Ferrier Research Institute, Victoria University of Wellington, Kelburn Parade, Wellington, 6012, New Zealand
| | - Benjamin R Duffus
- Institute of Biochemistry and Biology, Department of Molecular Enzymology, University of Potsdam, Karl-Liebknecht Strasse 24-25, 14476, Potsdam-Golm, Germany
| | - Jörg Bürger
- Max-Planck Institute of Molecular Genetics, Ihnestrasse 63-73, 14195, Berlin, Germany.,Charité, Institut für Medizinische Physik und Biophysik, Charitéplatz 1, 10117, Berlin, Germany
| | - Tobias Hartmann
- Institute of Biochemistry and Biology, Department of Molecular Enzymology, University of Potsdam, Karl-Liebknecht Strasse 24-25, 14476, Potsdam-Golm, Germany
| | - Thorsten Mielke
- Max-Planck Institute of Molecular Genetics, Ihnestrasse 63-73, 14195, Berlin, Germany
| | - Christian Teutloff
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Silke Leimkühler
- Institute of Biochemistry and Biology, Department of Molecular Enzymology, University of Potsdam, Karl-Liebknecht Strasse 24-25, 14476, Potsdam-Golm, Germany
| | - Petra Wendler
- Institute of Biochemistry and Biology, Department of Biochemistry, University of Potsdam, Karl-Liebknecht Strasse 24-25, 14476, Potsdam-Golm, Germany.
| |
Collapse
|
19
|
Kirk ML, Kc K. Molybdenum and Tungsten Cofactors and the Reactions They Catalyze. Met Ions Life Sci 2020; 20:/books/9783110589757/9783110589757-015/9783110589757-015.xml. [PMID: 32851830 PMCID: PMC8176780 DOI: 10.1515/9783110589757-015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
The last 20 years have seen a dramatic increase in our mechanistic understanding of the reactions catalyzed by pyranopterin Mo and W enzymes. These enzymes possess a unique cofactor (Moco) that contains a novel ligand in bioinorganic chemistry, the pyranopterin ene-1,2-dithiolate. A synopsis of Moco biosynthesis and structure is presented, along with our current understanding of the role Moco plays in enzymatic catalysis. Oxygen atom transfer (OAT) reactivity is discussed in terms of breaking strong metal-oxo bonds and the mechanism of OAT catalyzed by enzymes of the sulfite oxidase (SO) family that possess dioxo Mo(VI) active sites. OAT reactivity is also discussed in members of the dimethyl sulfoxide (DMSO) reductase family, which possess des-oxo Mo(IV) sites. Finally, we reveal what is known about hydride transfer reactivity in xanthine oxidase (XO) family enzymes and the formate dehydrogenases. The formal hydride transfer reactivity catalyzed by xanthine oxidase family enzymes is complex and cleaves substrate C-H bonds using a mechanism that is distinct from monooxygenases. The chapter primarily highlights developments in the field that have occurred since ~2000, which have contributed to our collective structural and mechanistic understanding of the three canonical pyranopterin Mo enzymes families: XO, SO, and DMSO reductase.
Collapse
|
20
|
Abstract
Here we highlight past work on metal-dithiolene interactions and how the unique electronic structure of the metal-dithiolene unit contributes to both the oxidative and reductive half reactions in pyranopterin molybdenum and tungsten enzymes. The metallodithiolene electronic structures detailed here were interrogated using multiple ground and excited state spectroscopic probes on the enzymes and their small molecule analogs. The spectroscopic results have been interpreted in the context of bonding and spectroscopic calculations, and the pseudo-Jahn-Teller effect. The dithiolene is a unique ligand with respect to its redox active nature, electronic synergy with the pyranopterin component of the molybdenum cofactor, and the ability to undergo chelate ring distortions that control covalency, reduction potential, and reactivity in pyranopterin molybdenum and tungsten enzymes.
Collapse
Affiliation(s)
- Jing Yang
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, Albuquerque, NM 87131-0001, USA
| | - John H. Enemark
- Department of Chemistry Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Martin L. Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, Albuquerque, NM 87131-0001, USA
- Correspondence: ; Tel.: +1-505-277-5992
| |
Collapse
|
21
|
Oliveira AR, Mota C, Mourato C, Domingos RM, Santos MFA, Gesto D, Guigliarelli B, Santos-Silva T, Romão MJ, Cardoso Pereira IA. Toward the Mechanistic Understanding of Enzymatic CO2 Reduction. ACS Catal 2020. [DOI: 10.1021/acscatal.0c00086] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ana Rita Oliveira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-157 Oeiras, Portugal
| | - Cristiano Mota
- UCIBIO, Applied Molecular Biosciences Unit, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Cláudia Mourato
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-157 Oeiras, Portugal
| | - Renato M. Domingos
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-157 Oeiras, Portugal
| | - Marino F. A. Santos
- UCIBIO, Applied Molecular Biosciences Unit, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Diana Gesto
- UCIBIO, Applied Molecular Biosciences Unit, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Bruno Guigliarelli
- Aix Marseille Université, CNRS, BIP, Laboratoire de Bioénergétique et Ingénierie des Protéines, Marseille 13402, France
| | - Teresa Santos-Silva
- UCIBIO, Applied Molecular Biosciences Unit, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Maria João Romão
- UCIBIO, Applied Molecular Biosciences Unit, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Inês A. Cardoso Pereira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-157 Oeiras, Portugal
| |
Collapse
|
22
|
Ingersol LJ, Yang J, Kc K, Pokhrel A, Astashkin AV, Weiner JH, Johnston CA, Kirk ML. Addressing Ligand-Based Redox in Molybdenum-Dependent Methionine Sulfoxide Reductase. J Am Chem Soc 2020; 142:2721-2725. [PMID: 31989824 DOI: 10.1021/jacs.9b11762] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A combination of pulsed EPR, CW EPR, and X-ray absorption spectroscopies has been employed to probe the geometric and electronic structure of the E. coli periplasmic molybdenum-dependent methionine sulfoxide reductase (MsrP). 17O and 1H pulsed EPR spectra show that the as-isolated Mo(V) enzyme form does not possess an exchangeable H2O/OH- ligand bound to Mo as found in the sulfite oxidizing enzymes of the same family. The nature of the unusual CW EPR spectrum has been re-evaluated in light of new data on the MsrP-N45R variant and related small-molecule analogues of the active site. These data point to a novel "thiol-blocked" [(PDT)MoVO(SCys)(thiolate)]- structure, which is supported by new EXAFS data. We discuss these new results in the context of ligand-based and metal-based redox chemistry in the enzymatic oxygen atom transfer reaction.
Collapse
Affiliation(s)
- Laura J Ingersol
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , United States
| | - Jing Yang
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , United States
| | - Khadanand Kc
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , United States
| | - Amrit Pokhrel
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , United States
| | - Andrei V Astashkin
- Department of Chemistry Biochemistry , University of Arizona , Tucson , Arizona 85721 , United States
| | - Joel H Weiner
- Department of Biochemistry , University of Alberta , 474 Medical Science Building , Edmonton , Alberta T6G 2H7 , Canada
| | - Christopher A Johnston
- Department of Biology , The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , United States
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , United States
| |
Collapse
|
23
|
|
24
|
Gisewhite DR, Nagelski AL, Cummins DC, Yap GPA, Burgmayer SJN. Modeling Pyran Formation in the Molybdenum Cofactor: Protonation of Quinoxalyl-Dithiolene Promoting Pyran Cyclization. Inorg Chem 2019; 58:5134-5144. [PMID: 30942584 PMCID: PMC6572731 DOI: 10.1021/acs.inorgchem.9b00194] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mononuclear Mo and W enzymes require a unique ligand known as molybdopterin (MPT). This ligand binds the metal through a dithiolene chelate, and the dithiolene bridges a reduced pyranopterin group. Pyran scission and formation have been proposed as a reaction of the MPT ligand that may occur within the enzymes to adjust reactivity at the Mo atom. We address this issue by investigating oxo-Mo(IV) model complexes containing dithiolenes substituted by pterin or quinoxaline and a hydroxyalkyl poised to form a pyran ring. While the pterin-dithiolene model complex exhibits a low energy, reversible pyran cyclization, here we report that pyran cyclization does not spontaneously occur in the quinoxalyl-dithiolene model. However, protonating the quinoxalyl-dithiolene model induces pyran cyclization forming an unstable, pyrano-quinoxalyl-dithiolene complex which subsequently dehydrates and rearranges to a pyrrolo-quinoxlyl-dithiolene complex that was previously characterized. The protonated pyrano-quinoxalyl-dithiolene complex was characterized by absorption spectroscopy and cyclic voltammetry, and these results suggest pyran cyclization leads to a significant change in the Mo electronic structure exhibited as a strong intraligand charge transfer (ILCT) transition and 370 mV positive shift of the Mo(V/IV) reduction potential. The influence of protonation on quinoxaline reactivity supports the hypothesis that the local protein environment in the second coordination sphere of molybdenum cofactor (Moco) could control pyran cyclization. The results also demonstrate that the remarkable chemical reactivity of the pterin-dithiolene ligand is subtly distinct and not reproduced by the simpler quinoxaline analog that is often used to replace pterin in synthetic Moco models.
Collapse
Affiliation(s)
- Douglas R. Gisewhite
- Department of Chemistry, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010, United States
| | - Alexandra L. Nagelski
- Department of Chemistry, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010, United States
| | - Daniel C. Cummins
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Glenn P. A. Yap
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Sharon J. N. Burgmayer
- Department of Chemistry, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010, United States
| |
Collapse
|
25
|
Moula G, Bose M, Sarkar S. Structurally characterized one oxo–desoxo bridged Mo 2–bis(dithiolene) complex and its interconversion to a discrete oxo or desoxo DMSOR model. NEW J CHEM 2019. [DOI: 10.1039/c9nj01020c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The dissymmetric binuclear complex1acts as a precursor of the molybdoenzyme models of the dimethylsulfoxide reductase (DMSOR) class.
Collapse
Affiliation(s)
- Golam Moula
- Nanoscience and Synthetic Leaf Laboratory at Downing Hall
- Centre for Healthcare Science and Technology
- Indian Institute of Engineering Science and Technology Shibpur Botanic Garden
- Howrah 711103
- India
| | - Moumita Bose
- Nanoscience and Synthetic Leaf Laboratory at Downing Hall
- Centre for Healthcare Science and Technology
- Indian Institute of Engineering Science and Technology Shibpur Botanic Garden
- Howrah 711103
- India
| | - Sabyasachi Sarkar
- Nanoscience and Synthetic Leaf Laboratory at Downing Hall
- Centre for Healthcare Science and Technology
- Indian Institute of Engineering Science and Technology Shibpur Botanic Garden
- Howrah 711103
- India
| |
Collapse
|
26
|
Fogeron T, Retailleau P, Chamoreau L, Li Y, Fontecave M. Pyranopterin Related Dithiolene Molybdenum Complexes as Homogeneous Catalysts for CO
2
Photoreduction. Angew Chem Int Ed Engl 2018; 57:17033-17037. [DOI: 10.1002/anie.201809084] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/19/2018] [Indexed: 01/14/2023]
Affiliation(s)
- Thibault Fogeron
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS Collège de France, Université Paris Sorbonne 11 Place Marcelin Berthelot 75231 Paris Cedex 05 France
| | - Pascal Retailleau
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301 Université Paris-Saclay 1, av.de la Terrasse 91198 Gif-sur-Yvette France
| | - Lise‐Marie Chamoreau
- Sorbonne Universités Université Paris Sorbonne Institut Parisien de Chimie Moléculaire, UMR 8232 CNRS 4 place Jussieu 75252 Paris Cedex 5 France
| | - Yun Li
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS Collège de France, Université Paris Sorbonne 11 Place Marcelin Berthelot 75231 Paris Cedex 05 France
| | - Marc Fontecave
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS Collège de France, Université Paris Sorbonne 11 Place Marcelin Berthelot 75231 Paris Cedex 05 France
| |
Collapse
|
27
|
Fogeron T, Retailleau P, Chamoreau L, Li Y, Fontecave M. Pyranopterin Related Dithiolene Molybdenum Complexes as Homogeneous Catalysts for CO
2
Photoreduction. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201809084] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Thibault Fogeron
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS Collège de France, Université Paris Sorbonne 11 Place Marcelin Berthelot 75231 Paris Cedex 05 France
| | - Pascal Retailleau
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301 Université Paris-Saclay 1, av.de la Terrasse 91198 Gif-sur-Yvette France
| | - Lise‐Marie Chamoreau
- Sorbonne Universités Université Paris Sorbonne Institut Parisien de Chimie Moléculaire, UMR 8232 CNRS 4 place Jussieu 75252 Paris Cedex 5 France
| | - Yun Li
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS Collège de France, Université Paris Sorbonne 11 Place Marcelin Berthelot 75231 Paris Cedex 05 France
| | - Marc Fontecave
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS Collège de France, Université Paris Sorbonne 11 Place Marcelin Berthelot 75231 Paris Cedex 05 France
| |
Collapse
|
28
|
Crystal structure of human mARC1 reveals its exceptional position among eukaryotic molybdenum enzymes. Proc Natl Acad Sci U S A 2018; 115:11958-11963. [PMID: 30397129 DOI: 10.1073/pnas.1808576115] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Biotransformation enzymes ensure a viable homeostasis by regulating reversible cycles of oxidative and reductive reactions. The metabolism of nitrogen-containing compounds is of high pharmaceutical and toxicological relevance because N-oxygenated metabolites derived from reactions mediated by cytochrome P450 enzymes or flavin-dependent monooxygenases are in some cases highly toxic or mutagenic. The molybdenum-dependent mitochondrial amidoxime-reducing component (mARC) was found to be an extremely efficient counterpart, which is able to reduce the full range of N-oxygenated compounds and thereby mediates detoxification reactions. However, the 3D structure of this enzyme was unknown. Here we present the high-resolution crystal structure of human mARC. We give detailed insight into the coordination of its molybdenum cofactor (Moco), the catalytic mechanism, and its ability to reduce a wide range of N-oxygenated compounds. The identification of two key residues will allow future discrimination between mARC paralogs and ensure correct annotation. Since our structural findings contradict in silico predictions that are currently made by online databases, we propose domain definitions for members of the superfamily of Moco sulfurase C-terminal (MOSC) domain-containing proteins. Furthermore, we present evidence for an evolutionary role of mARC for the emergence of the xanthine oxidase protein superfamily. We anticipate the hereby presented crystal structure to be a starting point for future descriptions of MOSC proteins, which are currently poorly structurally characterized.
Collapse
|
29
|
|
30
|
Stein BW, Yang J, Mtei R, Wiebelhaus NJ, Kersi DK, LePluart J, Lichtenberger DL, Enemark JH, Kirk ML. Vibrational Control of Covalency Effects Related to the Active Sites of Molybdenum Enzymes. J Am Chem Soc 2018; 140:14777-14788. [PMID: 30208274 DOI: 10.1021/jacs.8b08254] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A multitechnique spectroscopic and theoretical study of the Cp2M(benzenedithiolato) (M = Ti, V, Mo; Cp = η5-C5H5) series provides deep insight into dithiolene electronic structure contributions to electron transfer reactivity and reduction potential modulation in pyranopterin molybdenum enzymes. This work explains the magnitude of the dithiolene folding distortion and the concomitant changes in metal-ligand covalency that are sensitive to electronic structure changes as a function of d-electron occupancy in the redox orbital. It is shown that the large fold angle differences correlate with covalency, and the fold angle distortion is due to a pseudo-Jahn-Teller (PJT) effect. The PJT effect in these and related transition metal dithiolene systems arises from the small energy differences between metal and sulfur valence molecular orbitals, which uniquely poise these systems for dramatic geometric and electronic structure changes as the oxidation state changes. Herein, we have used a combination of resonance Raman, magnetic circular dichroism, electron paramagnetic resonance, and UV photoelectron spectroscopies to explore the electronic states involved in the vibronic coupling mechanism. Comparison between the UV photoelectron spectroscopy (UPS) of the d2 M = Mo complex and the resonance Raman spectra of the d1 M = V complex reveals the power of this combined spectroscopic approach. Here, we observe that the UPS spectrum of Cp2Mo(bdt) contains an intriguing vibronic progession that is dominated by a "missing-mode" that is composed of PJT-active distortions. We discuss the relationship of the PJT distortions to facile electron transfer in molybdenum enzymes.
Collapse
Affiliation(s)
- Benjamin W Stein
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC 032060, 1 University of New Mexico , Albuquerque , New Mexico 87131 , United States.,Chemistry Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Jing Yang
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC 032060, 1 University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Regina Mtei
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC 032060, 1 University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Nicholas J Wiebelhaus
- Department of Chemistry and Biochemistry , The University of Arizona , 1306 E. University Boulevard , Tucson , Arizona 85721 , United States
| | - Dominic K Kersi
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC 032060, 1 University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Jesse LePluart
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC 032060, 1 University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Dennis L Lichtenberger
- Department of Chemistry and Biochemistry , The University of Arizona , 1306 E. University Boulevard , Tucson , Arizona 85721 , United States
| | - John H Enemark
- Department of Chemistry and Biochemistry , The University of Arizona , 1306 E. University Boulevard , Tucson , Arizona 85721 , United States
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC 032060, 1 University of New Mexico , Albuquerque , New Mexico 87131 , United States
| |
Collapse
|
31
|
Gisewhite DR, Yang J, Williams BR, Esmail A, Stein B, Kirk ML, Burgmayer SJN. Implications of Pyran Cyclization and Pterin Conformation on Oxidized Forms of the Molybdenum Cofactor. J Am Chem Soc 2018; 140:12808-12818. [PMID: 30200760 DOI: 10.1021/jacs.8b05777] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The large family of mononuclear molybdenum and tungsten enzymes all possess the special ligand molybdopterin (MPT), which consists of a metal-binding dithiolene chelate covalently bound to a pyranopterin group. MPT pyran cyclization/scission processes have been proposed to modulate the reactivity of the metal center during catalysis. We have designed several small-molecule models for the Mo-MPT cofactor that allow detailed investigation into how pyran cyclization modulates electronic communication between the dithiolene and pterin moieties and how this cyclization alters the electronic environment of the molybdenum catalytic site. Using a combination of cyclic voltammetry, vibrational spectroscopy (FT-IR and rR), electronic absorption spectroscopy, and X-ray absorption spectroscopy, distinct changes in the Mo≡O stretching frequency, Mo(V/IV) reduction potential, and electronic structure across the pterin-dithiolene ligand are observed as a function of pyran ring closure. The results are significant, for they reveal that a dihydropyranopterin is electronically coupled into the Mo-dithiolene group due to a coplanar conformation of the pterin and dithiolene units, providing a mechanism for the electron-deficient pterin to modulate the Mo environment. A spectroscopic signature identified for the dihydropyranopterin-dithiolene ligand on Mo is a strong dithiolene → pterin charge transfer transition. In the absence of a pyran group bridge between pterin and dithiolene, the pterin rotates out of plane, largely decoupling the system. The results support a hypothesis that pyran cyclization/scission processes in MPT may function as a molecular switch to electronically couple and decouple the pterin and dithiolene to adjust the redox properties in certain pyranopterin molybdenum enzymes.
Collapse
Affiliation(s)
- Douglas R Gisewhite
- Department of Chemistry , Bryn Mawr College , Bryn Mawr , Pennsylvania 19010 , United States
| | - Jing Yang
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , United States
| | - Benjamin R Williams
- Department of Chemistry , Bryn Mawr College , Bryn Mawr , Pennsylvania 19010 , United States
| | - Alisha Esmail
- Department of Chemistry , Bryn Mawr College , Bryn Mawr , Pennsylvania 19010 , United States
| | - Benjamin Stein
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , United States
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , United States
| | - Sharon J N Burgmayer
- Department of Chemistry , Bryn Mawr College , Bryn Mawr , Pennsylvania 19010 , United States
| |
Collapse
|
32
|
Unraveling the inner workings of respiratory arsenate reductase. Proc Natl Acad Sci U S A 2018; 115:9051-9053. [PMID: 30150409 DOI: 10.1073/pnas.1812841115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
33
|
Abstract
Sulfite oxidase is a mononuclear molybdenum enzyme that oxidises sulfite to sulfate in many organisms, including man. Three different reaction mechanisms have been suggested, based on experimental and computational studies. Here, we study all three with combined quantum mechanical (QM) and molecular mechanical (QM/MM) methods, including calculations with large basis sets, very large QM regions (803 atoms) and QM/MM free-energy perturbations. Our results show that the enzyme is set up to follow a mechanism in which the sulfur atom of the sulfite substrate reacts directly with the equatorial oxo ligand of the Mo ion, forming a Mo-bound sulfate product, which dissociates in the second step. The first step is rate limiting, with a barrier of 39–49 kJ/mol. The low barrier is obtained by an intricate hydrogen-bond network around the substrate, which is preserved during the reaction. This network favours the deprotonated substrate and disfavours the other two reaction mechanisms. We have studied the reaction with both an oxidised and a reduced form of the molybdopterin ligand and quantum-refinement calculations indicate that it is in the normal reduced tetrahydro form in this protein.
Collapse
|
34
|
Kaufmann P, Duffus BR, Mitrova B, Iobbi-Nivol C, Teutloff C, Nimtz M, Jänsch L, Wollenberger U, Leimkühler S. Modulating the Molybdenum Coordination Sphere of Escherichia coli Trimethylamine N-Oxide Reductase. Biochemistry 2018; 57:1130-1143. [PMID: 29334455 DOI: 10.1021/acs.biochem.7b01108] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The well-studied enterobacterium Escherichia coli present in the human gut can reduce trimethylamine N-oxide (TMAO) to trimethylamine during anaerobic respiration. The TMAO reductase TorA is a monomeric, bis-molybdopterin guanine dinucleotide (bis-MGD) cofactor-containing enzyme that belongs to the dimethyl sulfoxide reductase family of molybdoenzymes. We report on a system for the in vitro reconstitution of TorA with molybdenum cofactors (Moco) from different sources. Higher TMAO reductase activities for TorA were obtained when using Moco sources containing a sulfido ligand at the molybdenum atom. For the first time, we were able to isolate functional bis-MGD from Rhodobacter capsulatus formate dehydrogenase (FDH), which remained intact in its isolated state and after insertion into apo-TorA yielded a highly active enzyme. Combined characterizations of the reconstituted TorA enzymes by electron paramagnetic resonance spectroscopy and direct electrochemistry emphasize that TorA activity can be modified by changes in the Mo coordination sphere. The combination of these results together with studies of amino acid exchanges at the active site led us to propose a novel model for binding of the substrate to the molybdenum atom of TorA.
Collapse
Affiliation(s)
- Paul Kaufmann
- Institute of Biochemistry and Biology, Department of Molecular Enzymology, University of Potsdam , 14476 Potsdam, Germany
| | - Benjamin R Duffus
- Institute of Biochemistry and Biology, Department of Molecular Enzymology, University of Potsdam , 14476 Potsdam, Germany
| | - Biljana Mitrova
- Institute of Biochemistry and Biology, Department of Molecular Enzymology, University of Potsdam , 14476 Potsdam, Germany
| | | | - Christian Teutloff
- Institute for Experimental Physics, Free University of Berlin , Arnimallee 14, 14195 Berlin, Germany
| | - Manfred Nimtz
- Helmholtz Center for Infection Research , Inhoffenstraße 7, 38124 Braunschweig, Germany
| | - Lothar Jänsch
- Helmholtz Center for Infection Research , Inhoffenstraße 7, 38124 Braunschweig, Germany
| | - Ulla Wollenberger
- Institute of Biochemistry and Biology, Department of Molecular Enzymology, University of Potsdam , 14476 Potsdam, Germany
| | - Silke Leimkühler
- Institute of Biochemistry and Biology, Department of Molecular Enzymology, University of Potsdam , 14476 Potsdam, Germany
| |
Collapse
|
35
|
Gohr S, Hrobárik P, Kaupp M. Four-Component Relativistic Density Functional Calculations of EPR Parameters for Model Complexes of Tungstoenzymes. J Phys Chem A 2017; 121:9106-9117. [DOI: 10.1021/acs.jpca.7b08768] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sebastian Gohr
- Institut
für Chemie, Theoretische Chemie/Quantenchemie, Technische Universität Berlin, Sekr. C7, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Peter Hrobárik
- Institut
für Chemie, Theoretische Chemie/Quantenchemie, Technische Universität Berlin, Sekr. C7, Straße des 17. Juni 135, 10623 Berlin, Germany
- Department
of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská dolina CH-2, Ilkovičova 6, SK-84215 Bratislava, Slovakia
| | - Martin Kaupp
- Institut
für Chemie, Theoretische Chemie/Quantenchemie, Technische Universität Berlin, Sekr. C7, Straße des 17. Juni 135, 10623 Berlin, Germany
| |
Collapse
|
36
|
Enemark JH. Consensus structures of the Mo(v) sites of sulfite-oxidizing enzymes derived from variable frequency pulsed EPR spectroscopy, isotopic labelling and DFT calculations. Dalton Trans 2017. [PMID: 28640289 DOI: 10.1039/c7dt01731f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sulfite-oxidizing enzymes from eukaryotes and prokaryotes have five-coordinate distorted square-pyramidal coordination about the molybdenum atom. The paramagnetic Mo(v) state is easily generated, and over the years four distinct CW EPR spectra have been identified, depending upon enzyme source and the reaction conditions, namely high and low pH (hpH and lpH), phosphate inhibited (Pi) and sulfite (or blocked). Extensive studies of these paramagnetic forms of sulfite-oxidizing enzymes using variable frequency pulsed electron spin echo (ESE) spectroscopy, isotopic labeling and density functional theory (DFT) calculations have led to the consensus structures that are described here. Errors in some of the previously proposed structures are corrected.
Collapse
Affiliation(s)
- John H Enemark
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85711, USA.
| |
Collapse
|
37
|
Culka M, Huwiler SG, Boll M, Ullmann GM. Breaking Benzene Aromaticity-Computational Insights into the Mechanism of the Tungsten-Containing Benzoyl-CoA Reductase. J Am Chem Soc 2017; 139:14488-14500. [PMID: 28918628 DOI: 10.1021/jacs.7b07012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aromatic compounds are environmental pollutants with toxic and carcinogenic properties. Despite the stability of aromatic rings, bacteria are able to degrade the aromatic compounds into simple metabolites and use them as growth substrates under oxic or even under anoxic conditions. In anaerobic microorganisms, most monocyclic aromatic growth substrates are converted to the central intermediate benzoyl-coenzyme A, which is enzymatically reduced to cyclohexa-1,5-dienoyl-CoA. The strictly anaerobic bacterium Geobacter metallireducens uses the class II benzoyl-CoA reductase complex for this reaction. The catalytic BamB subunit of this complex harbors an active site tungsten-bis-pyranopterin cofactor with the metal being coordinated by five protein/cofactor-derived sulfur atoms and a sixth, so far unknown, ligand. Although BamB has been biochemically and structurally characterized, its mechanism still remains elusive. Here we use continuum electrostatic and QM/MM calculations to model benzoyl-CoA reduction by BamB. We aim to elucidate the identity of the sixth ligand of the active-site tungsten ion together with the interplay of the electron and proton transfer events during the aromatic ring reduction. On the basis of our calculations, we propose that benzoyl-CoA reduction is initiated by a hydrogen atom transfer from a W(IV) species with an aqua ligand, yielding W(V)-[OH-] and a substrate radical intermediate. In the next step, a proton-assisted second electron transfer takes place with a conserved active-site histidine serving as the second proton donor. Interestingly, our calculations suggest that the electron for the second reduction step is taken from the pyranopterin cofactors rather than from the tungsten ion. The resulting cationic radical, which is distributed over both pyranopterins, is stabilized by conserved anionic amino acid residues. The stepwise mechanism of the reduction shows similarities to the Birch reduction known from organic chemistry. However, the strict coupling of protons and electrons allows the reaction to proceed under milder conditions.
Collapse
Affiliation(s)
- Martin Culka
- Computational Biochemistry, University of Bayreuth , Universitätsstrasse 30, NW I, 95447 Bayreuth, Germany
| | - Simona G Huwiler
- Microbiology, Faculty of Biology, University of Freiburg , Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Matthias Boll
- Microbiology, Faculty of Biology, University of Freiburg , Schänzlestrasse 1, 79104 Freiburg, Germany
| | - G Matthias Ullmann
- Computational Biochemistry, University of Bayreuth , Universitätsstrasse 30, NW I, 95447 Bayreuth, Germany
| |
Collapse
|
38
|
Dong C, Yang J, Reschke S, Leimkühler S, Kirk ML. Vibrational Probes of Molybdenum Cofactor-Protein Interactions in Xanthine Dehydrogenase. Inorg Chem 2017; 56:6830-6837. [PMID: 28590138 DOI: 10.1021/acs.inorgchem.7b00028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The pyranopterin dithiolene (PDT) ligand is an integral component of the molybdenum cofactor (Moco) found in all molybdoenzymes with the sole exception of nitrogenase. However, the roles of the PDT in catalysis are still unknown. The PDT is believed to be bound to the proteins by an extensive hydrogen-bonding network, and it has been suggested that these interactions may function to fine-tune Moco for electron- and atom-transfer reactivity in catalysis. Here, we use resonance Raman (rR) spectroscopy to probe Moco-protein interactions using heavy-atom congeners of lumazine, molecules that bind tightly to both wild-type xanthine dehydrogenase (wt-XDH) and its Q102G and Q197A variants following enzymatic hydroxylation to the corresponding violapterin product molecules. The resulting enzyme-product complexes possess intense near-IR absorption, allowing high-quality rR spectra to be collected on wt-XDH and the Q102G and Q197A variants. Small negative frequency shifts relative to wt-XDH are observed for the low-frequency Moco vibrations. These results are interpreted in the context of weak hydrogen-bonding and/or electrostatic interactions between Q102 and the -NH2 terminus of the PDT, and between Q197 and the terminal oxo of the Mo≡O group. The Q102A, Q102G, Q197A, and Q197E variants do not appreciably affect the kinetic parameters kred and kred/KD, indicating that a primary role for these glutamine residues is to stabilize and coordinate Moco in the active site of XO family enzymes but to not directly affect the catalytic throughput. Raman frequency shifts between wt-XDH and its Q102G variant suggest that the changes in the electron density at the Mo ion that accompany Mo oxidation during electron-transfer regeneration of the catalytically competent active site are manifest in distortions at the distant PDT amino terminus. This implies a primary role for the PDT as a conduit for facilitating enzymatic electron-transfer reactivity in xanthine oxidase family enzymes.
Collapse
Affiliation(s)
- Chao Dong
- Department of Chemistry and Chemical Biology, The University of New Mexico , MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - Jing Yang
- Department of Chemistry and Chemical Biology, The University of New Mexico , MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - Stefan Reschke
- Institute of Biochemistry and Biology, Department of Molecular Enzymology, University of Potsdam , 14476 Potsdam, Germany
| | - Silke Leimkühler
- Institute of Biochemistry and Biology, Department of Molecular Enzymology, University of Potsdam , 14476 Potsdam, Germany
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico , MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| |
Collapse
|
39
|
Rugor A, Wójcik-Augustyn A, Niedzialkowska E, Mordalski S, Staroń J, Bojarski A, Szaleniec M. Reaction mechanism of sterol hydroxylation by steroid C25 dehydrogenase - Homology model, reactivity and isoenzymatic diversity. J Inorg Biochem 2017; 173:28-43. [PMID: 28482186 DOI: 10.1016/j.jinorgbio.2017.04.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 04/24/2017] [Accepted: 04/26/2017] [Indexed: 11/29/2022]
Abstract
Steroid C25 dehydrogenase (S25DH) is a molybdenum-containing oxidoreductase isolated from the anaerobic Sterolibacterium denitrificans Chol-1S. S25DH is classified as 'EBDH-like' enzyme (EBDH, ethylbenzene dehydrogenase) and catalyzes the introduction of an OH group to the C25 atom of a sterol aliphatic side-chain. Due to its regioselectivity, S25DH is proposed as a catalyst in production of pharmaceuticals: calcifediol or 25-hydroxycholesterol. The aim of presented research was to obtain structural model of catalytic subunit α and investigate the reaction mechanism of the O2-independent tertiary carbon atom activation. Based on homology modeling and theoretical calculations, a S25DH α subunit model was for the first time characterized and compared to other S25DH-like isoforms. The molecular dynamics simulations of the enzyme-substrate complexes revealed two stable binding modes of a substrate, which are stabilized predominantly by van der Waals forces in the hydrophobic substrate channel. However, H-bond interactions involving polar residues with C3=O/C3-OH in the steroid ring appear to be responsible for positioning the substrate. These results may explain the experimental kinetic results which showed that 3-ketosterols are hydroxylated 5-10-fold faster than 3-hydroxysterols. The reaction mechanism was studied using QM:MM and QM-only cluster models. The postulated mechanism involves homolytic CH cleavage by the MoO ligand, giving rise to a radical intermediate with product obtained in an OH rebound process. The hypothesis was supported by kinetic isotopic effect (KIE) experiments involving 25,26,26,26-[2H]-cholesterol (4.5) and the theoretically predicted intrinsic KIE (7.0-7.2). Finally, we have demonstrated that the recombinant S25DH-like isoform catalyzes the same reaction as S25DH.
Collapse
Affiliation(s)
- Agnieszka Rugor
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland
| | - Anna Wójcik-Augustyn
- Department of Computational Biophysics and Bioinformatics, Faculty of Biochemistry, Biophysics and Biotechnology, JU, Krakow, Poland
| | - Ewa Niedzialkowska
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland
| | - Stefan Mordalski
- Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
| | - Jakub Staroń
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland; Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
| | - Andrzej Bojarski
- Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
| | - Maciej Szaleniec
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland.
| |
Collapse
|
40
|
The H-bond network surrounding the pyranopterins modulates redox cooperativity in the molybdenum- bis PGD cofactor in arsenite oxidase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1353-1362. [DOI: 10.1016/j.bbabio.2016.05.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 05/12/2016] [Accepted: 05/16/2016] [Indexed: 11/19/2022]
|
41
|
Affiliation(s)
- Charles G. Young
- Department of Chemistry and PhysicsLa Trobe Institute for Molecular ScienceLa Trobe University3086MelbourneVictoriaAustralia
| |
Collapse
|
42
|
Lee CC, Sickerman NS, Hu Y, Ribbe MW. YedY: A Mononuclear Molybdenum Enzyme with a Redox-Active Ligand? Chembiochem 2016; 17:453-5. [PMID: 26751730 DOI: 10.1002/cbic.201600004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Indexed: 11/07/2022]
Abstract
A recent electrochemical investigation suggests that the mononuclear molybdenum enzyme YdeY utilizes redox-active ligands during catalysis.
Collapse
Affiliation(s)
- Chi Chung Lee
- Department of Molecular Biology and Biochemistry, University of California in Irvine, 2230/2236 McGaugh Hall, Irvine, CA, 92697-3900, USA
| | - Nathaniel S Sickerman
- Department of Molecular Biology and Biochemistry, University of California in Irvine, 2230/2236 McGaugh Hall, Irvine, CA, 92697-3900, USA
| | - Yilin Hu
- Department of Molecular Biology and Biochemistry, University of California in Irvine, 2230/2236 McGaugh Hall, Irvine, CA, 92697-3900, USA.
| | - Markus W Ribbe
- Department of Molecular Biology and Biochemistry, University of California in Irvine, 2230/2236 McGaugh Hall, Irvine, CA, 92697-3900, USA. .,Department of Chemistry, University of California in Irvine, 2236 McGaugh Hall, Irvine, CA, 92697-2025, USA.
| |
Collapse
|
43
|
Archaeal Mo-Containing Glyceraldehyde Oxidoreductase Isozymes Exhibit Diverse Substrate Specificities through Unique Subunit Assemblies. PLoS One 2016; 11:e0147333. [PMID: 26808202 PMCID: PMC4726530 DOI: 10.1371/journal.pone.0147333] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 01/01/2016] [Indexed: 11/19/2022] Open
Abstract
Archaea use glycolytic pathways distinct from those found in bacteria and eukaryotes, where unique enzymes catalyze each reaction step. In this study, we isolated three isozymes of glyceraldehyde oxidoreductase (GAOR1, GAOR2 and GAOR3) from the thermoacidophilic archaeon Sulfolobus tokodaii. GAOR1-3 belong to the xanthine oxidoreductase superfamily, and are composed of a molybdo-pyranopterin subunit (L), a flavin subunit (M), and an iron-sulfur subunit (S), forming an LMS hetero-trimer unit. We found that GAOR1 is a tetramer of the STK17810/STK17830/STK17820 hetero-trimer, GAOR2 is a dimer of the STK23390/STK05620/STK05610 hetero-trimer, and GAOR3 is the STK24840/STK05620/STK05610 hetero-trimer. GAOR1-3 exhibited diverse substrate specificities for their electron donors and acceptors, due to their different L-subunits, and probably participate in the non-phosphorylative Entner-Doudoroff glycolytic pathway. We determined the crystal structure of GAOR2, as the first three-dimensional structure of an archaeal molybdenum-containing hydroxylase, to obtain structural insights into their substrate specificities and subunit assemblies. The gene arrangement and the crystal structure suggested that the M/S-complex serves as a structural scaffold for the binding of the L-subunit, to construct the three enzymes with different specificities. Collectively, our findings illustrate a novel principle of a prokaryotic multicomponent isozyme system.
Collapse
|
44
|
Yang J, Mogesa B, Basu P, Kirk ML. Large Ligand Folding Distortion in an Oxomolybdenum Donor-Acceptor Complex. Inorg Chem 2015; 55:785-93. [PMID: 26692422 DOI: 10.1021/acs.inorgchem.5b02252] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Interligand charge transfer is examined in the novel metallo-dithiolene complex MoO(SPh)2((i)Pr2Dt(0)) (where (i)Pr2Dt(0) = N,N'-isopropyl-piperazine-2,3-dithione). The title complex displays a remarkable 70° "envelope"-type fold of the five-membered dithiolene ring, which is bent upward toward the terminal oxo ligand. A combination of electronic absorption and resonance Raman spectroscopies have been used to probe the basic electronic structure responsible for the large fold-angle distortion. The intense charge transfer transition observed at ∼18 000 cm(-1) is assigned as a thiolate → dithione ligand-to-ligand charge transfer (LL'CT) transition that also possesses Mo(IV) → dithione charge transfer character. Strong orbital mixing between occupied and virtual orbitals with Mo(x(2)-y(2)) orbital character is derived from a strong pseudo Jahn-Teller effect, which drives the large fold-angle distortion to yield a double-well potential in the electronic ground state.
Collapse
Affiliation(s)
- Jing Yang
- Department of Chemistry and Chemical Biology, The University of New Mexico , MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - Benjamin Mogesa
- Department of Chemistry and Biochemistry, Duquesne University , Pittsburgh, Pennsylvania 15282, United States
| | - Partha Basu
- Department of Chemistry and Biochemistry, Duquesne University , Pittsburgh, Pennsylvania 15282, United States
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico , MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| |
Collapse
|
45
|
Chan CS, Turner RJ. Biogenesis of Escherichia coli DMSO Reductase: A Network of Participants for Protein Folding and Complex Enzyme Maturation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 883:215-34. [PMID: 26621470 DOI: 10.1007/978-3-319-23603-2_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Protein folding and structure have been of interest since the dawn of protein chemistry. Following translation from the ribosome, a protein must go through various steps to become a functional member of the cellular society. Every protein has a unique function in the cell and is classified on this basis. Proteins that are involved in cellular respiration are the bioenergetic workhorses of the cell. Bacteria are resilient organisms that can survive in diverse environments by fine tuning these workhorses. One class of proteins that allow survival under anoxic conditions are anaerobic respiratory oxidoreductases, which utilize many different compounds other than oxygen as its final electron acceptor. Dimethyl sulfoxide (DMSO) is one such compound. Respiration using DMSO as a final electron acceptor is performed by DMSO reductase, converting it to dimethyl sulfide in the process. Microbial respiration using DMSO is reviewed in detail by McCrindle et al. (Adv Microb Physiol 50:147-198, 2005). In this chapter, we discuss the biogenesis of DMSO reductase as an example of the participant network for complex iron-sulfur molybdoenzyme maturation pathways.
Collapse
Affiliation(s)
- Catherine S Chan
- Department of Biological Sciences, University of Calgary, BI156 Biological Sciences Bldg, 2500 University Dr NW, Calgary, AB, T2N 1N4, Canada.
| | - Raymond J Turner
- Department of Biological Sciences, University of Calgary, BI156 Biological Sciences Bldg, 2500 University Dr NW, Calgary, AB, T2N 1N4, Canada.
| |
Collapse
|
46
|
Electrochemical evidence that pyranopterin redox chemistry controls the catalysis of YedY, a mononuclear Mo enzyme. Proc Natl Acad Sci U S A 2015; 112:14506-11. [PMID: 26561582 DOI: 10.1073/pnas.1516869112] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A long-standing contradiction in the field of mononuclear Mo enzyme research is that small-molecule chemistry on active-site mimic compounds predicts ligand participation in the electron transfer reactions, but biochemical measurements only suggest metal-centered catalytic electron transfer. With the simultaneous measurement of substrate turnover and reversible electron transfer that is provided by Fourier-transformed alternating-current voltammetry, we show that Escherichia coli YedY is a mononuclear Mo enzyme that reconciles this conflict. In YedY, addition of three protons and three electrons to the well-characterized "as-isolated" Mo(V) oxidation state is needed to initiate the catalytic reduction of either dimethyl sulfoxide or trimethylamine N-oxide. Based on comparison with earlier studies and our UV-vis redox titration data, we assign the reversible one-proton and one-electron reduction process centered around +174 mV vs. standard hydrogen electrode at pH 7 to a Mo(V)-to-Mo(IV) conversion but ascribe the two-proton and two-electron transition occurring at negative potential to the organic pyranopterin ligand system. We predict that a dihydro-to-tetrahydro transition is needed to generate the catalytically active state of the enzyme. This is a previously unidentified mechanism, suggested by the structural simplicity of YedY, a protein in which Mo is the only metal site.
Collapse
|
47
|
Pimkov IV, Serli-Mitasev B, Peterson AA, Ratvasky SC, Hammann B, Basu P. Designing the Molybdopterin Core through Regioselective Coupling of Building Blocks. Chemistry 2015; 21:17057-72. [DOI: 10.1002/chem.201502845] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Indexed: 01/08/2023]
|
48
|
Wu SY, Rothery RA, Weiner JH. Pyranopterin Coordination Controls Molybdenum Electrochemistry in Escherichia coli Nitrate Reductase. J Biol Chem 2015; 290:25164-73. [PMID: 26297003 DOI: 10.1074/jbc.m115.665422] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Indexed: 11/06/2022] Open
Abstract
We test the hypothesis that pyranopterin (PPT) coordination plays a critical role in defining molybdenum active site redox chemistry and reactivity in the mononuclear molybdoenzymes. The molybdenum atom of Escherichia coli nitrate reductase A (NarGHI) is coordinated by two PPT-dithiolene chelates that are defined as proximal and distal based on their proximity to a [4Fe-4S] cluster known as FS0. We examined variants of two sets of residues involved in PPT coordination: (i) those interacting directly or indirectly with the pyran oxygen of the bicyclic distal PPT (NarG-Ser(719), NarG-His(1163), and NarG-His(1184)); and (ii) those involved in bridging the two PPTs and stabilizing the oxidation state of the proximal PPT (NarG-His(1092) and NarG-His(1098)). A S719A variant has essentially no effect on the overall Mo(VI/IV) reduction potential, whereas the H1163A and H1184A variants elicit large effects (ΔEm values of -88 and -36 mV, respectively). Ala variants of His(1092) and His(1098) also elicit large ΔEm values of -143 and -101 mV, respectively. An Arg variant of His(1092) elicits a small ΔEm of +18 mV on the Mo(VI/IV) reduction potential. There is a linear correlation between the molybdenum Em value and both enzyme activity and the ability to support anaerobic respiratory growth on nitrate. These data support a non-innocent role for the PPT moieties in controlling active site metal redox chemistry and catalysis.
Collapse
Affiliation(s)
- Sheng-Yi Wu
- From the Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Richard A Rothery
- From the Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Joel H Weiner
- From the Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| |
Collapse
|
49
|
Hahn A, Engelhard C, Reschke S, Teutloff C, Bittl R, Leimkühler S, Risse T. Strukturelle Einblicke in den Mo-Cofaktor-Einbau in Sulfitoxidase durch ortsspezifische Spinmarkierung. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201504772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
50
|
Hahn A, Engelhard C, Reschke S, Teutloff C, Bittl R, Leimkühler S, Risse T. Structural Insights into the Incorporation of the Mo Cofactor into Sulfite Oxidase from Site‐Directed Spin Labeling. Angew Chem Int Ed Engl 2015; 54:11865-9. [DOI: 10.1002/anie.201504772] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 06/29/2015] [Indexed: 12/13/2022]
Affiliation(s)
- Aaron Hahn
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany)
| | | | - Stefan Reschke
- Institut für Biochemie und Biologie, Universität Potsdam, Karl‐Liebknecht‐Str. 24‐25, 14476 Golm (Germany)
| | - Christian Teutloff
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany)
- Berlin Joint EPR Laboratory Freie Universität Berlin (Germany)
| | - Robert Bittl
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany)
- Berlin Joint EPR Laboratory Freie Universität Berlin (Germany)
| | - Silke Leimkühler
- Institut für Biochemie und Biologie, Universität Potsdam, Karl‐Liebknecht‐Str. 24‐25, 14476 Golm (Germany)
| | - Thomas Risse
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany)
- Berlin Joint EPR Laboratory Freie Universität Berlin (Germany)
| |
Collapse
|