Nucleotide sequence of the mxcQ and mxcE genes, required for methanol dehydrogenase synthesis in Methylobacterium organophilum XX: a two-component regulatory system

Xu, Hang; Janka, Jacqueline; Viebahn, Mareike; Hanson, Richard S.

doi:10.1099/13500872-141-10-2543

Cited by 22 publications

(22 citation statements)

References 22 publications

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“…The putative polypeptide encoded by this gene contains 208 amino acids with a predicted molecular mass of 26 kDa. This polypeptide shares 36% identity over 203 amino acids with MxaX of P. denitri¢cans [21] (accession number M92421), and 56% identity over 203 amino acids with both MxcE of M. organophilum XX [11], and M. extorquens AM1 (Springer, A.L. and Lidstrom, M.E., unpublished results).…”

Section: Sequence Of the Mxab Regionmentioning

confidence: 99%

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Sequence and characterization of mxaB, a response regulator involved in regulation of methanol oxidation, and of mxaW, a methanol-regulated gene in Methylobacterium extorquens AM1

Springer

1998

FEMS Microbiology Letters

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In the facultative serine cycle methylotroph Methylobacterium extorquens AM1, mxaB is required for regulation of methanol oxidation and is located at the end of a large cluster of methylotrophy genes that begins with mxaF. The sequence of mxaB has been obtained and indicates that the gene product is a member of the response regulator family. None of the open reading frames near mxaB showed sequence identity to sensor kinases. Complementation studies suggest a promoter may be located adjacent to mxaB. Another gene (mxaW) is present immediately upstream of mxaF, divergently transcribed from a methanolinducible promoter. The sequence in the region of mxaW was also obtained. MxaW showed no identity to known proteins. Mutations in mxaW and in an adjacent open reading frame, OrfR, had no effect on growth of M. extorquens AM1 on methanol or other substrates. The MxaW mutant had normal methanol dehydrogenase activity and normal transcription of the mxaF promoter. Therefore, the function of mxaW is unknown. z 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V.

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Section: Sequence Of the Mxab Regionmentioning

confidence: 99%

“…Five known genes, mxbDM, mxcQE and mxaB are required for transcription of mxaF in both M. extorquens AM1 [3,7] and M. organophilum XX [6]. MxbDM and mxcQE apparently encode regulatory proteins of the response regulator-sensor kinase family [10,11]. Four of the mxa genes, mxaACKL are required for insertion of calcium into MDH [1,4].…”

Section: Introductionmentioning

confidence: 99%

Sequence and characterization of mxaB, a response regulator involved in regulation of methanol oxidation, and of mxaW, a methanol-regulated gene in Methylobacterium extorquens AM1

Springer

1998

FEMS Microbiology Letters

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“…The mxa operon expression is known to be activated by at least two twocomponent systems, MxcQE and MxbDM, and an orphan response regulator, MxaB, in M. extorquens AM1 (20)(21)(22)(23). The M. buryatense genome lacks homologs of genes encoding MxcQE or MxbDM, but a homolog of the mxaB gene is located upstream of the mxa operon and is divergently transcribed (39).…”

Section: Lanthanides Mediate the Mdh Switch In M Buryatense 5gb1cmentioning

confidence: 99%

“…In methylotrophs, the mxa operon typically consists of genes encoding the large and small subunits of MDH (mxaF and mxaI, respectively), the cytochrome c electron acceptor (mxaG), proteins for calcium insertion (mxaACKL), and other genes of unknown function that are required for a functional MDH (6,19). Transcription of this operon in M. extorquens AM1 is controlled by at least two twocomponent systems, MxcQE and MxbDM, as well as by an orphan response regulator, MxaB (20)(21)(22)(23).…”

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confidence: 99%

XoxF Acts as the Predominant Methanol Dehydrogenase in the Type I Methanotroph Methylomicrobium buryatense

2016

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Many methylotrophic taxa harbor two distinct methanol dehydrogenase (MDH) systems for oxidizing methanol to formaldehyde: the well-studied calcium-dependent MxaFI type and the more recently discovered lanthanide-containing XoxF type. MxaFI has traditionally been accepted as the major functional MDH in bacteria that contain both enzymes. However, in this study, we present evidence that, in a type I methanotroph, Methylomicrobium buryatense, XoxF is likely the primary functional MDH in the environment. The addition of lanthanides increases xoxF expression and greatly reduces mxa expression, even under conditions in which calcium concentrations are almost 100-fold higher than lanthanide concentrations. Mutations in genes encoding the MDH enzymes validate our finding that XoxF is the major functional MDH, as XoxF mutants grow more poorly than MxaFI mutants under unfavorable culturing conditions. In addition, mutant and transcriptional analyses demonstrate that the lanthanide-dependent MDH switch operating in methanotrophs is mediated in part by the orphan response regulator MxaB, whose gene transcription is itself lanthanide responsive. IMPORTANCEAerobic methanotrophs, bacteria that oxidize methane for carbon and energy, require a methanol dehydrogenase enzyme to convert methanol into formaldehyde. The calcium-dependent enzyme MxaFI has been thought to primarily carry out methanol oxidation in methanotrophs. Recently, it was discovered that XoxF, a lanthanide-containing enzyme present in most methanotrophs, can also oxidize methanol. In a methanotroph with both MxaFI and XoxF, we demonstrate that lanthanides transcriptionally control genes encoding the two methanol dehydrogenases, in part by controlling expression of the response regulator MxaB. Lanthanides are abundant in the Earth's crust, and we demonstrate that micromolar amounts of lanthanides are sufficient to suppress MxaFI expression. Thus, we present evidence that XoxF acts as the predominant methanol dehydrogenase in a methanotroph.A n increasing surplus in the global methane budget exists due to human activity. The industrial use of microorganisms to convert methane into useful chemicals or biofuels represents one way to mitigate atmospheric methane (1, 2). Methanotrophs, or methane-oxidizing bacteria, utilize methane as their carbon and energy source and are prime candidates for the industrial bioconversion of methane (1). Renewed interest in the industrial use of methanotrophs has come about partially because of the discovery of rapidly growing strains and new tools for genetic manipulation, allowing for fast-paced metabolic engineering (3, 4). The success of metabolic engineering strategies in these methanotrophs depends upon a strong foundation of knowledge concerning the metabolic pathways that methanotrophs employ, both in the laboratory and in their natural environments, and an understanding of how various branches of metabolic pathways are regulated.The majority of methanotrophs have two systems for oxidizing methane to methanol: the parti...

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“…It is not known how the two sensor-regulator pairs, MxaZYX and FlhRS, which are both necessary for expression of the mxa genes, interact. In M. extorquens AM1 and in Methylobacterium organophilum XX, mxa gene expression is controlled by more than one sensor-regulator pair (26,33,34). In M. extorquens AM1, a regulatory hierarchy was found in which the sensor-regulator pair MxcQE controls expression of the sensor-regulator pair MxbDM (26).…”

Section: Discussionmentioning

confidence: 99%

Two-Component System That Regulates Methanol and Formaldehyde Oxidation in Paracoccus denitrificans

et al. 2001

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A chromosomal region encoding a two-component regulatory system, FlhRS, has been isolated from Paracoccus denitrificans. FlhRS-deficient mutants were unable to grow on methanol, methylamine, or choline as the carbon and energy source. Expression of the gene encoding glutathione-dependent formaldehyde dehydrogenase (fhlA) was undetectable in the mutant, and expression of the S-formylglutathione hydrolase gene (fghA) was reduced in the mutant background. In addition, methanol dehydrogenase was immunologically undetectable in cell extracts of FhlRS mutants. These results indicate that the FlhRS sensor-regulator pair is involved in the regulation of formaldehyde, methanol, and methylamine oxidation. The effect that the FlhRS proteins exert on the regulation of C 1 metabolism might be essential to maintain the internal concentration of formaldehyde below toxic levels.

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Nucleotide sequence of the mxcQ and mxcE genes, required for methanol dehydrogenase synthesis in Methylobacterium organophilum XX: a two-component regulatory system

Cited by 22 publications

References 22 publications

Sequence and characterization of mxaB, a response regulator involved in regulation of methanol oxidation, and of mxaW, a methanol-regulated gene in Methylobacterium extorquens AM1

Sequence and characterization of mxaB, a response regulator involved in regulation of methanol oxidation, and of mxaW, a methanol-regulated gene in Methylobacterium extorquens AM1

XoxF Acts as the Predominant Methanol Dehydrogenase in the Type I Methanotroph Methylomicrobium buryatense

Two-Component System That Regulates Methanol and Formaldehyde Oxidation in Paracoccus denitrificans

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