Molecular analysis of mxbD and mxbM, a putative sensor-regulator pair required for oxidation of methanol in Methylobacterium extorquens AM1
- 1 May 1997
- journal article
- Published by Microbiology Society in Microbiology
- Vol. 143 (5), 1737-1744
- https://doi.org/10.1099/00221287-143-5-1737
Abstract
Five genes are thought to be required for transcription of methanol oxidation genes in Methylobacterium strains. These putative regulatory genes include mxcQE, which encode a putative sensor-regulator pair, and mxbDM and mxaB, whose functions are less well-understood. In this study, mxbDM in Methylobacterium extorquens AM1 were shown to be required for expression of a xyIE transcriptional fusion to the structural gene for the large subunit of methanol dehydrogenase (mxaF), confirming the role of these genes in transcriptional regulation of mxaF. The nucleotide sequence suggests that mxbD encodes a histidiine protein kinase with two transmembrane domains and that mxbM encodes a DNA-binding response regulator. A xyIE transcriptional fusion to the putative mxbD promoter showed low-level expression in wild-type cells grown on one-carbon (C1) compounds and no detectable expression in cells grown on succinate. Deletion analysis of this promoter construct showed that the region 229-129 bp upstream of the start of mxbD is required for expression. The expression of the mxbD-xylE fusion was examined in each of the five known regulatory mutant classes. xyIE expression was reduced to non-detectable levels in MxcQ and MxcE mutants, but was not affected in the other regulatory mutants or in non-regulatory mutants defective in methanol oxidation. These results suggest a regulatory hierarchy in which the sensor-regulator pair MxcQE control expression of the sensor-regulator pair MxbDM, and MxbDM in turn control expression of a number of genes involved in methanol oxidation.Keywords
This publication has 35 references indexed in Scilit:
- The refined structure of the quinoprotein methanol dehydrogenase from Methylobacterium extorquens at 1.94 åStructure, 1995
- The structure and function of methanol dehydrogenase and related quinoproteins containing pyrrolo-quinoline quinoneBiochemical Journal, 1994
- Genetics of the serine cycle in Methylobacterium extorquens AM1: identification of sgaA and mtdA and sequences of sgaA, hprA, and mtdAJournal of Bacteriology, 1994
- Identification of a two‐component regulatory system controlling methanol dehydrogenase synthesis in Paracoccus denitrificansMolecular Microbiology, 1993
- The c-type cytochromes of methylotrophic bacteriaBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1992
- Characterization of a novel soluble c-type cytochrome in a moxD mutant of Methylobacterium extorquens AM1Journal of General Microbiology, 1990
- The moxFG region encodes four polypeptides in the methanol-oxidizing bacterium Methylobacterium sp. strain AM1Journal of Bacteriology, 1988
- Bacterial Oxidation of Methane and MethanolPublished by Elsevier ,1986
- Plasmids related to the broad host range vector, pRK290, useful for gene cloning and for monitoring gene expressionPlasmid, 1985
- Replication of an origin-containing derivative of plasmid RK2 dependent on a plasmid function provided in transProceedings of the National Academy of Sciences, 1979