Structural analysis of the L-methionine gamma-lyase gene from Pseudomonas putida.
The gene encoding L-methionine gamma-lyase from Pseudomonas putida was cloned and the primary structure of the enzyme was deduced from its nucleotide sequence. The L-methionine gamma-lyase gene was expressed in Escherichia coli. The amino acid sequences of BrCN-digested peptides agreed with the corresponding parts of the L-methionine gamma-lyase sequence determined from the gene structure. The polypeptide is composed of 398 amino acid residues with a calculated molecular weight of 42,626, corresponding to the subunit of the homotetrameric enzyme. The deduced amino acid sequence of L-methionine gamma-lyase only showed extensive homology with other well known alpha,gamma-elimination and/or gamma-replacement pyridoxal 5'-phosphate-dependent enzymes, such as cystathionine gamma-lyase, cystathionine gamma-synthase, and O-acetylhomoserine O-acetylserine sulfhydrylase, that participate in the biosynthesis of sulfur amino acids. However, the deduced essential cysteine residue of L-methionine gamma-lyase was not conserved in these enzymes. We confirmed the presence of a part of an open reading frame in the 3'-flanking region of the L-methionine gamma-lyase gene, which showed high homology with the N-terminal region of pyruvate dehydrogenase (lipoamide) from E. coli, suggesting that it participates in the degradative pathway for L-methionine together with L-methionine gamma-lyase.
Inoue
H
H
Department of Bioresources Chemistry, Faculty of Agriculture, Okayama University.
Inagaki
K
K
Sugimoto
M
M
Esaki
N
N
Soda
K
K
Tanaka
H
H
D000595:Amino Acid Sequence; D001483:Base Sequence; D013437:Carbon-Sulfur Lyases / Q000737:chemistry* / Q000235:genetics*; D003001:Cloning, Molecular; D015870:Gene Expression; D008715:Methionine / Q000378:metabolism; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D016958:Pseudomonas putida / Q000201:enzymology* / Q000235:genetics; D011768:Pyruvate Dehydrogenase Complex / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
D011768:Pyruvate Dehydrogenase Complex; D008715:Methionine; D013437:Carbon-Sulfur Lyases; C021558:L-methionine gamma-lyase