Identification of the incednine biosynthetic gene cluster: characterization of novel β-glutamate-β-decarboxylase IdnL3.
A biosynthetic gene cluster for the 24-membered macrolactam antibiotic incednine was identified from the producer strain, Streptomyces sp. ML694-90F3. Among the putative incednine biosynthetic enzymes, a novel pyridoxal 5'-phosphate (PLP)-dependent β-glutamate-β-decarboxylase, IdnL3, was functionally characterized in vitro by demonstrating its (S)-3-aminobutyrate-forming activity with β-glutamate in the presence of PLP. Because (S)-3-aminobutyrate is known for the direct precursor of incednine, this enzyme supplies the unique β-amino acid starter unit. The identified gene cluster encodes five characteristic β-amino acid carrying enzymes, consisting of a pathway-specific ATP-dependent ligase, a discrete acyl carrier protein (ACP), β-aminoacyl-ACP β-amino group-protecting ATP-dependent ligase, dipeptidyl-ACP:PKS-loading ACP dipeptidyltransferase and a terminal amino acid peptidase, which are completely conserved in β-amino acid-containing macrolactam biosynthetic gene clusters. Overall, a plausible biosynthetic pathway for incednine was proposed.
Department of Chemistry and Materials Science, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan.
Makoto
M
Takaishi
Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan.
Fumitaka
F
Kudo
Department of Chemistry and Materials Science, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan.
Tadashi
T
Eguchi
D000213:Acyl Carrier Protein / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D004187:Disaccharides / Q000096:biosynthesis*; D005798:Genes, Bacterial; D005968:Glutamate Decarboxylase / Q000235:genetics* / Q000378:metabolism*; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism; D007769:Lactams; D008954:Models, Biological; D008969:Molecular Sequence Data; D005810:Multigene Family; D016366:Open Reading Frames; D048630:Polyketide Synthases / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics*
D000213:Acyl Carrier Protein; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004187:Disaccharides; D007769:Lactams; C527896:incednine; D048630:Polyketide Synthases; D003577:Cytochrome P-450 Enzyme System; D016695:Glycosyltransferases; D005968:Glutamate Decarboxylase