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Versantvoort W, Pol A, Daumann LJ, Larrabee JA, Strayer AH, Jetten MS, van Niftrik L, Reimann J, Op den Camp HJ. Characterization of a novel cytochrome c as the electron acceptor of XoxF-MDH in the thermoacidophilic methanotroph Methylacidiphilum fumariolicum SolV. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1867:595-603. [DOI: 10.1016/j.bbapap.2019.04.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 03/28/2019] [Accepted: 04/02/2019] [Indexed: 11/29/2022]
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2
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Deng YW, Ro SY, Rosenzweig AC. Structure and function of the lanthanide-dependent methanol dehydrogenase XoxF from the methanotroph Methylomicrobium buryatense 5GB1C. J Biol Inorg Chem 2018; 23:1037-1047. [PMID: 30132076 PMCID: PMC6370294 DOI: 10.1007/s00775-018-1604-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/16/2018] [Indexed: 01/07/2023]
Abstract
In methylotrophic bacteria, which use one-carbon (C1) compounds as a carbon source, methanol is oxidized by pyrroloquinoline quinone (PQQ)-dependent methanol dehydrogenase (MDH) enzymes. Methylotrophic genomes generally encode two distinct MDHs, MxaF and XoxF. MxaF is a well-studied, calcium-dependent heterotetrameric enzyme whereas XoxF is a lanthanide-dependent homodimer. Recent studies suggest that XoxFs are likely the functional MDHs in many environments. In methanotrophs, methylotrophs that utilize methane, interactions between particulate methane monooxygenase (pMMO) and MxaF have been detected. To investigate the possibility of interactions between pMMO and XoxF, XoxF was isolated from the methanotroph Methylomicrobium buryatense 5GB1C (5G-XoxF). Purified 5G-XoxF exhibits a specific activity of 0.16 μmol DCPIP reduced min-1 mg-1. The 1.85 Å resolution crystal structure reveals a La(III) ion in the active site, in contrast to the calcium ion in MxaF. The overall fold is similar to other MDH structures, but 5G-XoxF is a monomer in solution. An interaction between 5G-XoxF and its cognate pMMO was detected by biolayer interferometry, with a KD value of 50 ± 17 μM. These results suggest an alternative model of MDH-pMMO association, in which a XoxF monomer may bind to pMMO, and underscore the potential importance of lanthanide-dependent MDHs in biological methane oxidation.
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Affiliation(s)
- Yue Wen Deng
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA,Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
| | - Soo Y. Ro
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA,Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
| | - Amy C. Rosenzweig
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA,Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
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Kumar S, Stecher G, Li M, Knyaz C, Tamura K. MEGA X: Molecular Evolutionary Genetics Analysis across Computing Platforms. Mol Biol Evol 2018; 35:1547-1549. [PMID: 29722887 DOI: 10.1007/0-387-30745-1_9] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023] Open
Abstract
The Molecular Evolutionary Genetics Analysis (Mega) software implements many analytical methods and tools for phylogenomics and phylomedicine. Here, we report a transformation of Mega to enable cross-platform use on Microsoft Windows and Linux operating systems. Mega X does not require virtualization or emulation software and provides a uniform user experience across platforms. Mega X has additionally been upgraded to use multiple computing cores for many molecular evolutionary analyses. Mega X is available in two interfaces (graphical and command line) and can be downloaded from www.megasoftware.net free of charge.
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Affiliation(s)
- Sudhir Kumar
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA
- Department of Biology, Temple University, Philadelphia, PA
- Center for Excellence in Genome Medicine and Research, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Glen Stecher
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA
| | - Michael Li
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA
| | - Christina Knyaz
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA
| | - Koichiro Tamura
- Research Center for Genomics and Bioinformatics, Tokyo Metropolitan University, Hachioji, Japan
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Japan
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Yoo YS, Han JS, Ahn CM, Kim CG. Comparative enzyme inhibitive methanol production by Methylosinus sporium from simulated biogas. ENVIRONMENTAL TECHNOLOGY 2015; 36:983-991. [PMID: 25267420 DOI: 10.1080/09593330.2014.971059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Methane in a simulated biogas converting to methanol under aerobic condition was comparatively assessed by inhibiting the activity of methanol dehydrogenase (MDH) of Methylosinus sporium using phosphate, NaCl, NH4Cl or EDTA in their varying concentrations. The highest amount of methane was indistinguishably diverted at the typical conditions regardless of the types of inhibitors: 35°C and pH 7 under a 0.4% (v/v) of biogas, specifically for <40 mM phosphate, 50 mM NaCl, 40 mM NH4Cl or 150 µM EDTA. The highest level of methanol was obtained for the addition of 40 mM phosphate, 100 mM NaCl, 40 mM NH4Cl or 50 µM EDTA. In other words, 0.71, 0.60, 0.66 and 0.66 mmol methanol was correspondingly generated by the oxidation of 1.3, 0.67, 0.74 and 1.3 mmol methane. It gave a methanol conversion rate of 54.7%, 89.9%, 89.6% and 47.8%, respectively. Among them, the maximum rate of methanol production was observed at 6.25 µmol/mg h for 100 mM NaCl. Regardless of types or concentrations of inhibitors differently used, methanol production could be nonetheless identically maximized when the MDH activity was limitedly hampered by up to 35%.
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Affiliation(s)
- Yeon-Sun Yoo
- a Department of Environmental Engineering , Inha University , Incheon , Republic of Korea
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Culpepper MA, Rosenzweig AC. Structure and protein-protein interactions of methanol dehydrogenase from Methylococcus capsulatus (Bath). Biochemistry 2014; 53:6211-9. [PMID: 25185034 PMCID: PMC4188263 DOI: 10.1021/bi500850j] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
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In
the initial steps of their metabolic pathway, methanotrophic
bacteria oxidize methane to methanol with methane monooxygenases (MMOs)
and methanol to formaldehyde with methanol dehydrogenases (MDHs).
Several lines of evidence suggest that the membrane-bound or particulate
MMO (pMMO) and MDH interact to form a metabolic supercomplex. To further
investigate the possible existence of such a supercomplex, native
MDH from Methylococcus capsulatus (Bath) has been
purified and characterized by size exclusion chromatography with multi-angle
light scattering and X-ray crystallography. M. capsulatus (Bath) MDH is primarily a dimer in solution, although an oligomeric
species with a molecular mass of ∼450–560 kDa forms
at higher protein concentrations. The 2.57 Å resolution crystal
structure reveals an overall fold and α2β2 dimeric architecture similar to those of other MDH structures.
In addition, biolayer interferometry studies demonstrate specific
protein–protein interactions between MDH and M. capsulatus (Bath) pMMO as well as between MDH and the truncated recombinant
periplasmic domains of M. capsulatus (Bath) pMMO
(spmoB). These interactions exhibit KD values of 833 ± 409 nM and 9.0 ± 7.7 μM, respectively.
The biochemical data combined with analysis of the crystal lattice
interactions observed in the MDH structure suggest a model in which
MDH and pMMO associate not as a discrete, stoichiometric complex but
as a larger assembly scaffolded by the intracytoplasmic membranes.
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Affiliation(s)
- Megen A Culpepper
- Departments of Molecular Biosciences and Chemistry, Northwestern University , Evanston, Illinois 60208, United States
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Suzuki R, Lisdiyanti P, Komagata K, Uchimura T. MxaF gene, a gene encoding alpha subunit of methanol dehydrogenase in and false growth of acetic acid bacteria on methanol. J GEN APPL MICROBIOL 2009; 55:101-10. [PMID: 19436127 DOI: 10.2323/jgam.55.101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
MxaF gene, a gene encoding alpha subunit of methanol dehydrogenase, was investigated for acetic acid bacteria, and growth on methanol was examined for the bacteria by using various media. Of 21 strains of acetic acid bacteria studied, Acidomonas methanolica strains showed the presence of mxaF gene exclusively, and grew on a defined medium containing methanol. Further, none of the strains tested of which the growth on methanol had been previously reported, except for Acidomonas methanolica, showed the presence of mxaF gene or the growth on methanol. Precautions were taken against false growth on compounds used for identification of bacteria.
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Affiliation(s)
- Rei Suzuki
- Laboratory of General and Applied Microbiology, Department of Applied Biology and Chemistry, Faculty of Applied Bioscience, Tokyo University of Agriculture, Tokyo, Japan
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Ishikawa K, Toda-Murakoshi Y, Ohnishi F, Kondo K, Osumi T, Asano K. Medium Composition Suitable for l-Lysine Production by Methylophilus methylotrophus in Fed-Batch Cultivation. J Biosci Bioeng 2008; 106:574-9. [DOI: 10.1263/jbb.106.574] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Accepted: 08/24/2008] [Indexed: 11/17/2022]
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Anthony C. The quinoprotein dehydrogenases for methanol and glucose. Arch Biochem Biophys 2004; 428:2-9. [PMID: 15234264 DOI: 10.1016/j.abb.2004.03.038] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2004] [Revised: 03/19/2004] [Indexed: 11/29/2022]
Abstract
This review summarises our current understanding of two of the main types of quinoprotein dehydrogenase in which pyrroloquinoline quinone (PQQ) is the only prosthetic group. These are the soluble methanol dehydrogenase and the membrane glucose dehydrogenase (mGDH). The membrane GDH has an additional N-terminal domain by which it is tightly anchored to the membrane, and a periplasmic domain whose structure has been modelled on the X-ray structure of the alpha-subunit of MDH which contains PQQ in the active site. This review discusses their structures and mechanisms, concentrating particularly on the pathways for electron transfer from the reduced PQQ, through the protein, to their electron acceptors. In MDH, this is the specific cytochrome c(L), the electron transfer pathway probably involving the unique disulphide ring in the active site. By contrast, mGDH contains a permanently bound ubiquinone, which acts as a single electron carrier, mediating electron transfer through the protein to the membrane ubiquinone.
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Affiliation(s)
- Christopher Anthony
- School of Biological Sciences, University of Southampton, Southampton SO16 7PX, UK.
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Xia ZX, Dai WW, He YN, White SA, Mathews FS, Davidson VL. X-ray structure of methanol dehydrogenase from Paracoccus denitrificans and molecular modeling of its interactions with cytochrome c-551i. J Biol Inorg Chem 2003; 8:843-54. [PMID: 14505072 DOI: 10.1007/s00775-003-0485-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2003] [Accepted: 08/14/2003] [Indexed: 10/26/2022]
Abstract
The X-ray structure of methanol dehydrogenase (MEDH) from Paracoccus denitrificans (MEDH-PD) was determined at 2.5 A resolution using molecular replacement based on the structure of MEDH from Methylophilus methylotrophus W3A1 (MEDH-WA). The overall structures from the two bacteria are similar to each other except that the former has a longer C-terminal tail in each subunit and shows local differences in several insertion regions. The "X-ray sequence" of the segment alphaGly444-alphaLeu452 was established, including one insertion and seven replacements compared with the reported sequence. The primary electron acceptor of MEDH-PD is cytochrome c-551i (Cyt c551i). Based on the crystal structure of MEDH-PD and of the published structure of Cyt c551i, their interactions were investigated by molecular modeling. As a guide and starting point, the covalently attached cytochrome and PQQ domains of the alcohol dehydrogenase from Pseudomonas putida HK5 (ADH2B) were used. In the modeling, two molecules of Cyt c551i could be accommodated in their interaction with the MEDH heterotetramer in accordance with the two-fold molecular symmetry of the latter. Two models are proposed, in both of which electrostatic and hydrogen bonding interactions make major contributions to inter-protein binding. One of these models involves salt bridges from alphaArg99 of MEDH to the heme propionic acids of Cyt c551i and the other involves salt bridges from alphaArg426 of MEDH to Glu112 of Cyt c551i. Both involve salt bridges from alphaLys93 of MEDH to Asp75 of Cyt c551i. The size and nature of the cytochrome/quinoprotein heterodimer interfaces and calculations of electronic coupling and electron transfer rates favor one of these models over the other.
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Affiliation(s)
- Zong-Xiang Xia
- State Key Laboratrory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, China
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10
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Affiliation(s)
- C Anthony
- Division of Biochemistry and Molecular Biology, School of Biological Sciences, University of Southampton, Southampton SO16 7PX
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Jongejan A, Machado SS, Jongejan JA. The enantioselectivity of quinohaemoprotein alcohol dehydrogenases: mechanistic and structural aspects. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s1381-1177(99)00063-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Pyrrolo-quinoline quinone (PQQ) is the non-covalently bound prosthetic group of many quinoproteins catalysing reactions in the periplasm of Gram-negative bacteria. Most of these involve the oxidation of alcohols or aldose sugars. PQQ is formed by fusion of glutamate and tyrosine, but details of the biosynthetic pathway are not known; a polypeptide precursor in the cytoplasm is probably involved, the completed PQQ being transported into the periplasm. In addition to the soluble methanol dehydrogenase of methylotrophs, there are three classes of alcohol dehydrogenases; type I is similar to methanol dehydrogenase; type II is a soluble quinohaemoprotein, having a C-terminal extension containing haem C; type III is similar but it has two additional subunits (one of which is a multihaem cytochrome c), bound in an unusual way to the periplasmic membrane. There are two types of glucose dehydrogenase; one is an atypical soluble quinoprotein which is probably not involved in energy transduction. The more widely distributed glucose dehydrogenases are integral membrane proteins, bound to the membrane by transmembrane helices at the N-terminus. The structures of the catalytic domains of type III alcohol dehydrogenase and membrane glucose dehydrogenase have been modelled successfully on the methanol dehydrogenase structure (determined by X-ray crystallography). Their mechanisms are likely to be similar in many ways and probably always involve a calcium ion (or other divalent cation) at the active site. The electron transport chains involving the soluble alcohol dehydrogenases usually consist only of soluble c-type cytochromes and the appropriate terminal oxidases. The membrane-bound quinohaemoprotein alcohol dehydrogenases pass electrons to membrane ubiquinone which is then oxidized directly by ubiquinol oxidases. The electron acceptor for membrane glucose dehydrogenase is ubiquinone which is subsequently oxidized directly by ubiquinol oxidases or by electron transfer chains involving cytochrome bc1, cytochrome c and cytochrome c oxidases. The function of most of these systems is to produce energy for growth on alcohol or aldose substrates, but there is some debate about the function of glucose dehydrogenases in those bacteria which contain one or more alternative pathways for glucose utilization. Synthesis of the quinoprotein respiratory systems requires production of PQQ, haem and the dehydrogenase subunits, transport of these into the periplasm, and incorporation together with divalent cations, into active quinoproteins and quinohaemoproteins. Six genes required for regulation of synthesis of methanol dehydrogenase have been identified in Methylobacterium, and there is evidence that two, two-component regulatory systems are involved.
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Affiliation(s)
- P M Goodwin
- Division of Biochemistry and Molecular Biology, School of Biological Sciences, University of Southampton, UK
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Anthony C, Ghosh M. The structure and function of the PQQ-containing quinoprotein dehydrogenases. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1998; 69:1-21. [PMID: 9670773 DOI: 10.1016/s0079-6107(97)00020-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Bacterial methanol and glucose dehydrogenases containing a novel type of prosthetic group, subsequently identified as pyrrolo-quinoline quinone (PQQ), were first described about 30 years ago. Quinoproteins were originally defined as proteins containing PQQ but this definition has since been broadened to include those proteins containing other types of quinone-containing prosthetic groups, and the X-ray structures of representatives of each type of quinoprotein have recently been published. This review is mainly concerned with the structure and function of the PQQ-containing methanol dehydrogenase, whose structure has been determined at high resolution, and related proteins. Their basic structure consists of a 'propeller' fold superbarrel made up of 8-sheet 'propeller blades' which are held together by novel tryptophan-docking motifs. In methanol dehydrogenase the PQQ in the active site is coordinated to a Ca2+ ion and is maintained in position by a stacked tryptophan and a novel 8-membered ring structure made up of a disulphide bridge between adjacent cysteine residues. This review describes these features and discusses them in relation to previously proposed mechanisms for this enzyme.
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Affiliation(s)
- C Anthony
- Division of Biochemistry and Molecular Biology, School of Biological Sciences, University of Southampton, U.K.
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Abstract
This review is concerned with the structure and function of the quinoprotein enzymes, sometimes called quinoenzymes. These have prosthetic groups containing quinones, the name thus being analogous to the flavoproteins containing flavin prosthetic groups. Pyrrolo-quinoline quinone (PQQ) is non-covalently attached, whereas tryptophan tryptophylquinone (TTQ), topaquinone (TPQ) and lysine tyrosylquinone (LTQ) are derived from amino acid residues in the backbone of the enzymes. The mechanisms of the quinoproteins are reviewed and related to their recently determined three-dimensional structures. As expected, the quinone structures in the prosthetic groups play important roles in the mechanisms. A second common feature is the presence of a catalytic base (aspartate) at the active site which initiates the reactions by abstracting a proton from the substrate, and it is likely to be involved in multiple reactions in the mechanism. A third common feature of these enzymes is that the first part of the reaction produces a reduced prosthetic group; this part of the mechanism is fairly well understood. This is followed by an oxidative phase involving electron transfer reactions which remain poorly understood. In both types of dehydrogenase (containing PQQ and TTQ), electrons must pass from the reduced prosthetic group to redox centres in a second recipient protein (or protein domain), whereas in amine oxidases (containing TPQ or LTQ), electrons must be transferred to molecular oxygen by way of a redox-active copper ion in the protein.
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Affiliation(s)
- C Anthony
- Biochemistry Department, University of Southampton, U.K
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Dales SL, Anthony C. The interaction of methanol dehydrogenase and its cytochrome electron acceptor. Biochem J 1995; 312 ( Pt 1):261-5. [PMID: 7492322 PMCID: PMC1136253 DOI: 10.1042/bj3120261] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A fluorescence method is described for direct measurement of the interaction between methanol dehydrogenase (MDH) and its electron acceptor cytochrome cL. This has permitted a distinction to be made between factors affecting electron transfer and those affecting the initial binding or docking process. It was confirmed that the initial interaction is electrostatic, but previous conclusions with respect to the mechanism of EDTA inhibition have been modified. It is proposed that the initial 'docking' of MDH and cytochrome cL is by way of ionic interactions between lysyl residues on its surface and carboxylate groups on the surface of cytochrome cL. This interaction is not inhibited by EDTA, which we suggest acts by binding to nearby lysyl residues, thus preventing movement of the 'docked' cytochrome to its optimal position for electron transfer, which probably involves interaction with the hydrophobic funnel in the surface of MDH.
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Affiliation(s)
- S L Dales
- Biochemistry Department, University of Southampton, U.K
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Anthony C, Ghosh M, Blake CC. The structure and function of methanol dehydrogenase and related quinoproteins containing pyrrolo-quinoline quinone. Biochem J 1994; 304 ( Pt 3):665-74. [PMID: 7818466 PMCID: PMC1137385 DOI: 10.1042/bj3040665] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- C Anthony
- Department of Biochemistry, University of Southampton, U.K
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Matsushita K, Toyama H, Adachi O. Respiratory chains and bioenergetics of acetic acid bacteria. Adv Microb Physiol 1994; 36:247-301. [PMID: 7942316 DOI: 10.1016/s0065-2911(08)60181-2] [Citation(s) in RCA: 227] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- K Matsushita
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Japan
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Richardson IW, Anthony C. Characterization of mutant forms of the quinoprotein methanol dehydrogenase lacking an essential calcium ion. Biochem J 1992; 287 ( Pt 3):709-15. [PMID: 1332681 PMCID: PMC1133066 DOI: 10.1042/bj2870709] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Methanol dehydrogenase (MDH) from Methylobacterium extorquens, Methylophilus methylotrophus, Paracoccus denitrificans and Hyphomicrobium X all contained a single atom of Ca2+ per alpha 2 beta 2 tetramer. The role of Ca2+ was investigated using the MDH from Methylobacterium extorquens. This was shown to be similar to the MDH from Hyphomicrobium X in having 2 mol of prosthetic group (pyrroloquinoline quinine; PQQ) per mol of tetramer, the PQQ being predominantly in the semiquinone form. MDH isolated from the methanol oxidation mutants MoxA-, K- and L- contained no Ca2+. They were identical with the enzyme isolated from wild-type bacteria with respect to molecular size, subunit configuration, pI, N-terminal amino acid sequence and stability under denaturing conditions (low pH, high urea and high guanidinium chloride) and in the nature and content of the prosthetic group (2 mol of PQQ per mol of MDH). They differed in their lack of Ca2+, the oxidation state of the extracted PQQ (fully oxidized), absence of the semiquinone form of PQQ in the enzyme, reactivity with the suicide inhibitor cyclopropanol and absorption spectrum, which indicated that PQQ is bound differently from that in normal MDH. Incubation of MDH from the mutants in calcium salts led to irreversible time-dependent reconstitution of full activity concomitant with restoration of a spectrum corresponding to that of fully reduced normal MDH. It is concluded that Ca2+ in MDH is directly or indirectly involved in binding PQQ in the active site. The MoxA, K and L proteins may be involved in maintaining a high Ca2+ concentration in the periplasm. It is more likely, however, that they fill a 'chaperone' function, stabilizing a configuration of MDH which permits incorporation of low concentrations of Ca2+ into the protein.
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Affiliation(s)
- I W Richardson
- Department of Biochemistry, University of Southampton, U.K
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Chan H, Anthony C. Characterisation of a red form of methanol dehydrogenase from the marine methylotrophMethylophaga marina. FEMS Microbiol Lett 1992. [DOI: 10.1111/j.1574-6968.1992.tb05478.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Anthony C. The c-type cytochromes of methylotrophic bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1992. [DOI: 10.1016/0005-2728(92)90181-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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