title: Genome of Methylobacillus flagellatus, molecular basis for obligate methylotrophy, and polyphyletic origin of methylotrophy.
abstract: Along with methane, methanol and methylated amines represent important biogenic atmospheric constituents; thus, not only methanotrophs but also nonmethanotrophic methylotrophs play a significant role in global carbon cycling. The complete genome of a model obligate methanol and methylamine utilizer, Methylobacillus flagellatus (strain KT) was sequenced. The genome is represented by a single circular chromosome of approximately 3 Mbp, potentially encoding a total of 2,766 proteins. Based on genome analysis as well as the results from previous genetic and mutational analyses, methylotrophy is enabled by methanol and methylamine dehydrogenases and their specific electron transport chain components, the tetrahydromethanopterin-linked formaldehyde oxidation pathway and the assimilatory and dissimilatory ribulose monophosphate cycles, and by a formate dehydrogenase. Some of the methylotrophy genes are present in more than one (identical or nonidentical) copy. The obligate dependence on single-carbon compounds appears to be due to the incomplete tricarboxylic acid cycle, as no genes potentially encoding alpha-ketoglutarate, malate, or succinate dehydrogenases are identifiable. The genome of M. flagellatus was compared in terms of methylotrophy functions to the previously sequenced genomes of three methylotrophs, Methylobacterium extorquens (an alphaproteobacterium, 7 Mbp), Methylibium petroleiphilum (a betaproteobacterium, 4 Mbp), and Methylococcus capsulatus (a gammaproteobacterium, 3.3 Mbp). Strikingly, metabolically and/or phylogenetically, the methylotrophy functions in M. flagellatus were more similar to those in M. capsulatus and M. extorquens than to the ones in the more closely related M. petroleiphilum species, providing the first genomic evidence for the polyphyletic origin of methylotrophy in Betaproteobacteria.
authors.affiliation: University of Washington, Seattle, USA. milachis@u.washington.edu
authors.forename: Ludmila
authors.initials: L
authors.lastname: Chistoserdova
authors.forename: Alla
authors.initials: A
authors.lastname: Lapidus
authors.forename: Cliff
authors.initials: C
authors.lastname: Han
authors.forename: Lynne
authors.initials: L
authors.lastname: Goodwin
authors.forename: Liz
authors.initials: L
authors.lastname: Saunders
authors.forename: Tom
authors.initials: T
authors.lastname: Brettin
authors.forename: Roxanne
authors.initials: R
authors.lastname: Tapia
authors.forename: Paul
authors.initials: P
authors.lastname: Gilna
authors.forename: Susan
authors.initials: S
authors.lastname: Lucas
authors.forename: Paul M
authors.initials: PM
authors.lastname: Richardson
authors.forename: Mary E
authors.initials: ME
authors.lastname: Lidstrom
mesh_terms: D053898:Biosynthetic Pathways; D002952:Citric Acid Cycle; D019295:Computational Biology; D019143:Evolution, Molecular; D016680:Genome, Bacterial; D000432:Methanol / Q000378:metabolism*; D008744:Methylamines / Q000378:metabolism*; D020631:Methylobacillus / Q000235:genetics* / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010802:Phylogeny; D017422:Sequence Analysis, DNA
chemical_list: D008744:Methylamines; C027451:methylamine; D000432:Methanol