FIG 1.

(A) Arrangement of genes encoding the N-methylglutamate pathway on the chromosome of nonmethylotrophic proteobacteria (like Agrobacterium tumefaciens) and methylotrophic proteobacteria (like Hyphomicrobium sp. strain MC1 and Methylobacterium extorquens PA1). Blue, genes encoding the four subunits of NMGDH (mgdABCD); red, genes encoding the three subunits of NMGS (mgsABC); orange, a single gene encoding GMAS (gmaS). TR, transcriptional regulator; purU, gene encoding formyl-tetrahydrofolate hydrolase; folD, gene encoding bifunctional methylene tetrahydrofolate dehydrogenase and methenyl tetrahydrofolate cyclohydrolase; TCA, tricarboxylic acid.