US EPA

1055790 

Journal Article 

{gamma}-Glutamylmethylamide is an essential intermediate in the metabolism of methylamine by Methylocella silvestris 

Chen, Y; Scanlan, J; Song, L; Crombie, A; Rahman, MT; Schäfer, H; Murrell, JC 

2010 

Yes 

Applied and Environmental Microbiology
ISSN: 0099-2240
EISSN: 1098-5336 

76 

13 

4530-4537 

English 

20472738 

10.1128/AEM.00739-10 

WOS:000279082800046 

https://search.proquest.com/docview/1368573914?accountid=171501
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Methylocella silvestris BL2, a facultative methane utilizer, can grow on monomethylamine (MMA) as a sole carbon and nitrogen source. No activity of MMA dehydrogenase was detectable. Instead, this bacterium utilizes a methylated amino acid pathway (gamma-glutamylmethylamide [GMA] and N-methylglutamate [NMG]) for MMA metabolism. The activities of the two key enzymes in this pathway, GMA synthetase and NMG dehydrogenase, were found when the bacterium was grown on MMA. GMA was detected by high-performance liquid chromatography-mass spectrometry only when the bacterium was grown on MMA but not when it was grown on methanol. Proteomic analysis of soluble and membrane fractions of the proteome from MMA- and methanol-grown cultures revealed that an eight-gene cluster (Msil2632 to Msil2639) was induced by MMA and cotranscribed as an operon, as shown by reverse transcription-PCR. GMA-dissimilating enzyme activity was also detected when it was grown on MMA. Formaldehyde and ammonium production from GMA was dependent on glutamate but not on alpha-ketoglutarate. Marker exchange mutagenesis of a putative GMAS gene homologue (gmas, Msil2635) within this eight-gene cluster, with a kanamycin gene cassette, abolished growth of M. silvestris on MMA as either a sole carbon or a sole nitrogen source. Overall, our results suggest that gmas is essential in MMA metabolism by M. silvestris. 

Methylocella; amino acids; bacteria; enzyme activity; enzymes; formaldehyde; glutamates; mass spectrometry; metabolism; methane; methanol; methylamine; mutagenesis; nitrogen; proteome; reverse transcriptase polymerase chain reaction; article