Nucleotide sequence of the metH gene of Escherichia coli K-12 and comparison with that of Salmonella typhimurium LT2.
The Escherichia coli K-12 metH gene, encoding the vitamin B12-dependent homocysteine transmethylase, is located between iclR and lysC in the 91-min region of the chromosome. The metH gene has been sequenced and reveals an open reading frame of 3600 bp encoding a polypeptide of 1200 amino acids (aa) with a calculated Mr of 132 628. The first 414 aa of the deduced polypeptide sequence are 92% identical to the 414 aa deduced from the partially sequenced Salmonella typhimurium LT2 metH gene. In-frame fusions of metH to lacZ were used to confirm the reading frame of the metH gene and to study its regulation. metH was repressed tenfold, presumably indirectly, by L-methionine and the metJ gene product, while vitamin B12 did not induce de novo synthesis of MetH.
Unité des Leptospires, Institut Pasteur, Paris, France.
I G
IG
Old
D
D
Margarita
R E
RE
Glass
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I
Saint Girons
D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005798:Genes, Bacterial; D050904:Homocysteine S-Methyltransferase; D008780:Methyltransferases / Q000235:genetics*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D015183:Restriction Mapping; D012486:Salmonella typhimurium / Q000201:enzymology / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
D008780:Methyltransferases; D050904:Homocysteine S-Methyltransferase