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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.
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Affiliation(s)
| | - Martin L. Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, NM 87131, USA
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2
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Al-Attar S, Rendon J, Sidore M, Duneau JP, Seduk F, Biaso F, Grimaldi S, Guigliarelli B, Magalon A. Gating of Substrate Access and Long-Range Proton Transfer in Escherichia coli Nitrate Reductase A: The Essential Role of a Remote Glutamate Residue. ACS Catal 2021. [DOI: 10.1021/acscatal.1c03988] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Sinan Al-Attar
- Laboratoire de Chimie Bactérienne (UMR7283), IMM, IM2B, Aix Marseille Université, CNRS, 13402 Marseille, France
| | - Julia Rendon
- Laboratoire de Bioénergétique et Ingénierie des Protéines (UMR7281), IMM, IM2B, Aix Marseille Université, CNRS, 13402 Marseille, France
| | - Marlon Sidore
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (UMR7255), IMM, IM2B, Aix Marseille Université, CNRS, 13402 Marseille, France
| | - Jean-Pierre Duneau
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (UMR7255), IMM, IM2B, Aix Marseille Université, CNRS, 13402 Marseille, France
| | - Farida Seduk
- Laboratoire de Chimie Bactérienne (UMR7283), IMM, IM2B, Aix Marseille Université, CNRS, 13402 Marseille, France
| | - Frédéric Biaso
- Laboratoire de Bioénergétique et Ingénierie des Protéines (UMR7281), IMM, IM2B, Aix Marseille Université, CNRS, 13402 Marseille, France
| | - Stéphane Grimaldi
- Laboratoire de Bioénergétique et Ingénierie des Protéines (UMR7281), IMM, IM2B, Aix Marseille Université, CNRS, 13402 Marseille, France
| | - Bruno Guigliarelli
- Laboratoire de Bioénergétique et Ingénierie des Protéines (UMR7281), IMM, IM2B, Aix Marseille Université, CNRS, 13402 Marseille, France
| | - Axel Magalon
- Laboratoire de Chimie Bactérienne (UMR7283), IMM, IM2B, Aix Marseille Université, CNRS, 13402 Marseille, France
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3
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Long C, Dai L, E C, Da LT, Yu J. Allosteric regulation in CRISPR/Cas1-Cas2 protospacer acquisition mediated by DNA and Cas2. Biophys J 2021; 120:3126-3137. [PMID: 34197800 PMCID: PMC8390960 DOI: 10.1016/j.bpj.2021.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 05/10/2021] [Accepted: 06/04/2021] [Indexed: 11/19/2022] Open
Abstract
Cas1 and Cas2 are highly conserved proteins across clustered-regularly-interspaced-short-palindromic-repeat-Cas systems and play a significant role in protospacer acquisition. Based on crystal structure of twofold symmetric Cas1-Cas2 in complex with dual-forked protospacer DNA (psDNA), we conducted all-atom molecular dynamics simulations to study the psDNA binding, recognition, and response to cleavage on the protospacer-adjacent-motif complementary sequence, or PAMc, of Cas1-Cas2. In the simulation, we noticed that two active sites of Cas1 and Cas1’ bind asymmetrically to two identical PAMc on the psDNA captured from the crystal structure. For the modified psDNA containing only one PAMc, as that to be recognized by Cas1-Cas2 in general, our simulations show that the non-PAMc association site of Cas1-Cas2 remains destabilized until after the stably bound PAMc being cleaved at the corresponding association site. Thus, long-range correlation appears to exist upon the PAMc cleavage between the two active sites (∼10 nm apart) on Cas1-Cas2, which can be allosterically mediated by psDNA and Cas2 and Cas2’ in bridging. To substantiate such findings, we conducted repeated runs and further simulated Cas1-Cas2 in complex with synthesized psDNA sequences psL and psH, which have been measured with low and high frequency in acquisition, respectively. Notably, such intersite correlation becomes even more pronounced for the Cas1-Cas2 in complex with psH but remains low for the Cas1-Cas2 in complex with psL. Hence, our studies demonstrate that PAMc recognition and cleavage at one active site of Cas1-Cas2 may allosterically regulate non-PAMc association or even cleavage at the other site, and such regulation can be mediated by noncatalytic Cas2 and DNA protospacer to possibly support the ensued psDNA acquisition.
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Affiliation(s)
- Chunhong Long
- School of Science, Chongqing University of Posts and Telecommunications, Chongqing, China
| | - Liqiang Dai
- Shenzhen JL Computational Science and Applied Research Institute, Shenzhen, China; Beijing Computational Science Research Center, Beijing, China
| | - Chao E
- Beijing Computational Science Research Center, Beijing, China
| | - Lin-Tai Da
- Shanghai Center for Systems Biomedicine, Shanghai JiaoTong University, Shanghai, China
| | - Jin Yu
- Departments of Physics and Astronomy and Chemistry, NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, California.
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Zuchan K, Baymann F, Baffert C, Brugna M, Nitschke W. The dyad of the Y-junction- and a flavin module unites diverse redox enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148401. [PMID: 33684340 DOI: 10.1016/j.bbabio.2021.148401] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 02/09/2021] [Accepted: 02/16/2021] [Indexed: 11/26/2022]
Abstract
The concomitant presence of two distinctive polypeptide modules, which we have chosen to denominate as the "Y-junction" and the "flavin" module, is observed in 3D structures of enzymes as functionally diverse as complex I, NAD(P)-dependent [NiFe]-hydrogenases and NAD(P)-dependent formate dehydrogenases. Amino acid sequence conservation furthermore suggests that both modules are also part of NAD(P)-dependent [FeFe]-hydrogenases for which no 3D structure model is available yet. The flavin module harbours the site of interaction with the substrate NAD(P) which exchanges two electrons with a strictly conserved flavin moiety. The Y-junction module typically contains four iron-sulphur centres arranged to form a Y-shaped electron transfer conduit and mediates electron transfer between the flavin module and the catalytic units of the respective enzymes. The Y-junction module represents an electron transfer hub with three potential electron entry/exit sites. The pattern of specific redox centres present both in the Y-junction and the flavin module is correlated to present knowledge of these enzymes' functional properties. We have searched publicly accessible genomes for gene clusters containing both the Y-junction and the flavin module to assemble a comprehensive picture of the diversity of enzymes harbouring this dyad of modules and to reconstruct their phylogenetic relationships. These analyses indicate the presence of the dyad already in the last universal common ancestor and the emergence of complex I's EFG-module out of a subgroup of NAD(P)- dependent formate dehydrogenases.
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Affiliation(s)
- Kilian Zuchan
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France
| | - Frauke Baymann
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France
| | - Carole Baffert
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France
| | - Myriam Brugna
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France.
| | - Wolfgang Nitschke
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France
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5
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Functional mononuclear molybdenum enzymes: challenges and triumphs in molecular cloning, expression, and isolation. J Biol Inorg Chem 2020; 25:547-569. [PMID: 32279136 DOI: 10.1007/s00775-020-01787-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/30/2020] [Indexed: 10/24/2022]
Abstract
Mononuclear molybdenum enzymes catalyze a variety of reactions that are essential in the cycling of nitrogen, carbon, arsenic, and sulfur. For decades, the structure and function of these crucial enzymes have been investigated to develop a fundamental knowledge for this vast family of enzymes and the chemistries they carry out. Therefore, obtaining abundant quantities of active enzyme is necessary for exploring this family's biochemical capability. This mini-review summarizes the methods for overexpressing mononuclear molybdenum enzymes in the context of the challenges encountered in the process. Effective methods for molybdenum cofactor synthesis and incorporation, optimization of expression conditions, improving isolation of active vs. inactive enzyme, incorporation of additional prosthetic groups, and inclusion of redox enzyme maturation protein chaperones are discussed in relation to the current molybdenum enzyme literature. This article summarizes the heterologous and homologous expression studies providing underlying patterns and potential future directions.
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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
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Abstract
Books with titles like 'The Call of the Wild' seemed to set a path for a life. Thus, I would be an explorer-a plan that did not work out so well, at least at first. On leaving school I got a job as a 'Works Chemist Improver', testing Ni catalysts for the hydrogenation of phenol to cyclohexanol. Taking night classes I passed enough exams to study geology at Queen Mary College, London. Armed thus I travelled to the Solomon Islands where geology is a 'happening'! Next was Canada to visit a mine sunk into a 1.5 billion year old Pb-Zn orebody precipitated from submarine hot springs. At last I reached the Yukon to prospect for silver. Thence to Ireland researching what I also took to be 'exhalative' (i.e. hot spring-related) Pb-Zn orebodies. While there in 1979, the discovery of 350°C metal-bearing acidic waters issuing from submarine Black Smoker chimneys in the Pacific sent us searching for fossil examples in the Irish mines. However, the chimneys we found were more like chemical gardens than Black Smokers, a finding that made us think about the emergence of life. After all, what better for life's emergence than to have a membrane comprising Fe minerals dosed with Ni in our chimneys to mediate the 'hydrogenation' of CO2-life's job anyway. Indeed, such a membrane would keep redox and pH disequilibria at bay, just like biological membranes. At the same time, my field research among Alpine ophiolites-ocean floor mafic rocks obducted to the Alps-indicated that alkaline waters bearing H2 and CH4 were a result of serpentinization, a process that must have operated in all ocean floors over all time. Thus it was that we could predict the Lost City hydrothermal field 10 years before its discovery in the North Atlantic in the year 2000. Lost City comprises a number of alkaline springs at up to 90°C that produce carbonate and brucite (Mg[OH]2) chimneys. We had surmised that Ni-enriched FeS chimneys would have precipitated at comparable alkaline springs issuing into a metal-rich carbonic ocean on the very early Earth (inducing membrane potentials comparable to those capable of succouring all life, and presumably, sufficient to drive life into being). However, our laboratory precipitates also revealed green rust, thought to be the precursor to the magnetite now comprising the Archaean Banded Iron Formations. We now look upon green rust, also known as fougèrite, as the tangible, base fractal of life.
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Affiliation(s)
- Michael J. Russell
- NASA Astrobiology Institute, NASA Ames Research Center, Moffett Field, CA, USA
- http://bip.cnrs-mrs.fr/bip09/AHVics.html
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Duval S, Baymann F, Schoepp-Cothenet B, Trolard F, Bourrié G, Grauby O, Branscomb E, Russell MJ, Nitschke W. Fougerite: the not so simple progenitor of the first cells. Interface Focus 2019; 9:20190063. [PMID: 31641434 DOI: 10.1098/rsfs.2019.0063] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2019] [Indexed: 12/22/2022] Open
Abstract
We here review the extraordinary mineralogical properties of green rusts and their naturally occurring form, fougerite, and discuss the pertinence of these properties within the alkaline hydrothermal vent (AHV) hypothesis for life's emergence. We put forward an extended version of the AHV scenario which enhances the conformity between extant life and its earliest progenitor by extensively making use of fougerite's mechanistic and catalytic particularities.
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Affiliation(s)
- Simon Duval
- Aix Marseille Université, CNRS, BIP (UMR 7281), Marseille, France
| | - Frauke Baymann
- Aix Marseille Université, CNRS, BIP (UMR 7281), Marseille, France
| | | | | | | | - Olivier Grauby
- Aix Marseille Université, CINaM (UMR 7325), Luminy, France
| | - Elbert Branscomb
- Carl R. Woese Institute for Genomic Biology, and Department of Physics, University of Illinois, Urbana, IL 61801, USA
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9
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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.
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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
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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.
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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
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11
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Baymann F, Schoepp-Cothenet B, Duval S, Guiral M, Brugna M, Baffert C, Russell MJ, Nitschke W. On the Natural History of Flavin-Based Electron Bifurcation. Front Microbiol 2018; 9:1357. [PMID: 30018596 PMCID: PMC6037941 DOI: 10.3389/fmicb.2018.01357] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 06/05/2018] [Indexed: 11/23/2022] Open
Abstract
Electron bifurcation is here described as a special case of the continuum of electron transfer reactions accessible to two-electron redox compounds with redox cooperativity. We argue that electron bifurcation is foremost an electrochemical phenomenon based on (a) strongly inverted redox potentials of the individual redox transitions, (b) a high endergonicity of the first redox transition, and (c) an escapement-type mechanism rendering completion of the first electron transfer contingent on occurrence of the second one. This mechanism is proposed to govern both the traditional quinone-based and the newly discovered flavin-based versions of electron bifurcation. Conserved and variable aspects of the spatial arrangement of electron transfer partners in flavoenzymes are assayed by comparing the presently available 3D structures. A wide sample of flavoenzymes is analyzed with respect to conserved structural modules and three major structural groups are identified which serve as basic frames for the evolutionary construction of a plethora of flavin-containing redox enzymes. We argue that flavin-based and other types of electron bifurcation are of primordial importance to free energy conversion, the quintessential foundation of life, and discuss a plausible evolutionary ancestry of the mechanism.
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Affiliation(s)
- Frauke Baymann
- CNRS, BIP, UMR 7281, IMM FR3479, Aix-Marseille University, Marseille, France
| | | | - Simon Duval
- CNRS, BIP, UMR 7281, IMM FR3479, Aix-Marseille University, Marseille, France
| | - Marianne Guiral
- CNRS, BIP, UMR 7281, IMM FR3479, Aix-Marseille University, Marseille, France
| | - Myriam Brugna
- CNRS, BIP, UMR 7281, IMM FR3479, Aix-Marseille University, Marseille, France
| | - Carole Baffert
- CNRS, BIP, UMR 7281, IMM FR3479, Aix-Marseille University, Marseille, France
| | - Michael J. Russell
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
| | - Wolfgang Nitschke
- CNRS, BIP, UMR 7281, IMM FR3479, Aix-Marseille University, Marseille, France
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12
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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.
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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
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Watson C, Niks D, Hille R, Vieira M, Schoepp-Cothenet B, Marques AT, Romão MJ, Santos-Silva T, Santini JM. Electron transfer through arsenite oxidase: Insights into Rieske interaction with cytochrome c. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2017; 1858:865-872. [PMID: 28801050 PMCID: PMC5574378 DOI: 10.1016/j.bbabio.2017.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 07/05/2017] [Accepted: 08/05/2017] [Indexed: 11/25/2022]
Abstract
Arsenic is a widely distributed environmental toxin whose presence in drinking water poses a threat to >140 million people worldwide. The respiratory enzyme arsenite oxidase from various bacteria catalyses the oxidation of arsenite to arsenate and is being developed as a biosensor for arsenite. The arsenite oxidase from Rhizobium sp. str. NT-26 (a member of the Alphaproteobacteria) is a heterotetramer consisting of a large catalytic subunit (AioA), which contains a molybdenum centre and a 3Fe-4S cluster, and a small subunit (AioB) containing a Rieske 2Fe-2S cluster. Stopped-flow spectroscopy and isothermal titration calorimetry (ITC) have been used to better understand electron transfer through the redox-active centres of the enzyme, which is essential for biosensor development. Results show that oxidation of arsenite at the active site is extremely fast with a rate of >4000s-1 and reduction of the electron acceptor is rate-limiting. An AioB-F108A mutation results in increased activity with the artificial electron acceptor DCPIP and decreased activity with cytochrome c, which in the latter as demonstrated by ITC is not due to an effect on the protein-protein interaction but instead to an effect on electron transfer. These results provide further support that the AioB F108 is important in electron transfer between the Rieske subunit and cytochrome c and its absence in the arsenite oxidases from the Betaproteobacteria may explain the inability of these enzymes to use this electron acceptor.
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Affiliation(s)
- Cameron Watson
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, WC1E 6BT, United Kingdom
| | - Dimitri Niks
- Department of Biochemistry, University of California; Riverside, Riverside, CA 92521, USA
| | - Russ Hille
- Department of Biochemistry, University of California; Riverside, Riverside, CA 92521, USA
| | - Marta Vieira
- UCIBIO-Requimte, Department of Chemistry, Faculty of Sciences and Technology, Universidade Nova de Lisboa, Portugal
| | | | - Alexandra T Marques
- UCIBIO-Requimte, Department of Chemistry, Faculty of Sciences and Technology, Universidade Nova de Lisboa, Portugal
| | - Maria João Romão
- UCIBIO-Requimte, Department of Chemistry, Faculty of Sciences and Technology, Universidade Nova de Lisboa, Portugal
| | - Teresa Santos-Silva
- UCIBIO-Requimte, Department of Chemistry, Faculty of Sciences and Technology, Universidade Nova de Lisboa, Portugal
| | - Joanne M Santini
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, WC1E 6BT, United Kingdom.
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Russell MJ, Nitschke W. Methane: Fuel or Exhaust at the Emergence of Life? ASTROBIOLOGY 2017; 17:1053-1066. [PMID: 28949766 PMCID: PMC5655419 DOI: 10.1089/ast.2016.1599] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 03/20/2017] [Indexed: 05/28/2023]
Abstract
As many of the methanogens first encountered at hydrothermal vents were thermophilic to hyperthermophilic and comprised one of the lower roots of the evolutionary tree, it has been assumed that methanogenesis was one of the earliest, if not the earliest, pathway to life. It being well known that hydrothermal springs associated with serpentinization also bore abiotic methane, it had been further assumed that emergent biochemistry merely adopted and quickened this supposed serpentinization reaction. Yet, recent hydrothermal experiments simulating serpentinization have failed to generate methane so far, thus casting doubt on this assumption. The idea that the inverse view is worthy of debate, that is, that methanotrophy was the earlier, is stymied by the "fact" that methanotrophy itself has been termed "reverse methanogenesis," so allotting the methanogens the founding pedigree. Thus, attempting to suggest instead that methanogenesis might be termed reverse methanotrophy would require "unlearning"-a challenge to the subconscious! Here we re-examine the "impossibility" of methanotrophy predating methanogenesis as in what we have termed the "denitrifying methanotrophic acetogenic pathway." Advantages offered by such thinking are that methane would not only be a fuel but also a ready source of reduced carbon to combine with formate or carbon monoxide-available in hydrothermal fluids-to generate acetate, a target molecule of the first autotrophs. And the nitrate/nitrite required for the putative oxidation of methane with activated NO would also be a ready source of fixed nitrogen for amination reactions. Theoretical conditions for such a putative pathway would be met in a hydrothermal green rust-bearing exhalative pile and associated chimneys subject to proton and electron counter gradients. This hypothesis could be put to test in a high-pressure hydrothermal reaction chamber in which a cool carbonate/nitrate/nitrite-bearing early acidulous ocean simulant is juxtaposed across a precipitate membrane to an alkaline solution of hydrogen and methane. Key Words: Green rust-Methanotrophy-Nitrate reduction-Emergence of life. Astrobiology 17, 1053-1066.
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Affiliation(s)
- Michael J. Russell
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | - Wolfgang Nitschke
- CNRS/Aix-Marseille University, BIP UMR 7281, IMM FR 3479, Marseille, France
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15
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Rendon J, Biaso F, Ceccaldi P, Toci R, Seduk F, Magalon A, Guigliarelli B, Grimaldi S. Elucidating the Structures of the Low- and High-pH Mo(V) Species in Respiratory Nitrate Reductase: A Combined EPR, 14,15N HYSCORE, and DFT Study. Inorg Chem 2017; 56:4423-4435. [DOI: 10.1021/acs.inorgchem.6b03129] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Julia Rendon
- Aix Marseille Univ, CNRS, BIP, Marseille, France
| | | | - Pierre Ceccaldi
- Aix Marseille Univ, CNRS, BIP, Marseille, France
- Aix Marseille Univ, CNRS, LCB, Marseille, France
| | - René Toci
- Aix Marseille Univ, CNRS, LCB, Marseille, France
| | - Farida Seduk
- Aix Marseille Univ, CNRS, LCB, Marseille, France
| | - Axel Magalon
- Aix Marseille Univ, CNRS, LCB, Marseille, France
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