This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Studer, A. Articles by Vuilleumier, S. Search for Related Content PubMed PubMed Citation Articles by Studer, A. Articles by Vuilleumier, S.

Chloromethane-Induced Genes Define a Third C₁ Utilization Pathway in Methylobacterium chloromethanicum CM4

Institut für Mikrobiologie, ETH Zürich, CH-8092 Zürich, Switzerland

Received 2 January 2002/ Accepted 27 March 2002

Methylobacterium chloromethanicum CM4 is an aerobic -proteobacterium capable of growth with chloromethane as the sole carbon and energy source. Two proteins, CmuA and CmuB, were previously purified and shown to catalyze the dehalogenation of chloromethane and the vitamin B₁₂-mediated transfer of the methyl group of chloromethane to tetrahydrofolate. Three genes located near cmuA and cmuB, designated metF, folD and purU and encoding homologs of methylene tetrahydrofolate (methylene-H₄folate) reductase, methylene-H₄folate dehydrogenase-methenyl-H₄folate cyclohydrolase and formyl-H₄folate hydrolase, respectively, suggested the existence of a chloromethane-specific oxidation pathway from methyl-tetrahydrofolate to formate in strain CM4. Hybridization and PCR analysis indicated that these genes were absent in Methylobacterium extorquens AM1, which is unable to grow with chloromethane. Studies with transcriptional xylE fusions demonstrated the chloromethane-dependent expression of these genes. Transcriptional start sites were mapped by primer extension and allowed to define three transcriptional units, each likely comprising several genes, that were specifically expressed during growth of strain CM4 with chloromethane. The DNA sequences of the deduced promoters display a high degree of sequence conservation but differ from the Methylobacterium promoters described thus far. As shown previously for purU, inactivation of the metF gene resulted in a CM4 mutant unable to grow with chloromethane. Methylene-H₄folate reductase activity was detected in a cell extract of strain CM4 only in the presence of chloromethane but not in the metF mutant. Taken together, these data provide evidence that M. chloromethanicum CM4 requires a specific set of tetrahydrofolate-dependent enzymes for growth with chloromethane.

This article has been cited by other articles:

• Kasai, D., Masai, E., Miyauchi, K., Katayama, Y., Fukuda, M. (2005). Characterization of the Gallate Dioxygenase Gene: Three Distinct Ring Cleavage Dioxygenases Are Involved in Syringate Degradation by Sphingomonas paucimobilis SYK-6. J. Bacteriol. 187: 5067-5074 [Abstract] [Full Text]  
• Borodina, E., McDonald, I. R., Murrell, J. C. (2004). Chloromethane-Dependent Expression of the cmu Gene Cluster of Hyphomicrobium chloromethanicum. Appl. Environ. Microbiol. 70: 4177-4186 [Abstract] [Full Text]  
• Marx, C. J., Lidstrom, M. E. (2004). Development of an insertional expression vector system for Methylobacterium extorquens AM1 and generation of null mutants lacking mtdA and/or fch. Microbiology 150: 9-19 [Abstract] [Full Text]