title: Extensive mutational analysis of modular-iterative mixed polyketide biosynthesis of lankacidin in Streptomyces rochei.
abstract: Extensive mutations of lankacidin synthase genes were carried out to analyze the modular-iterative mixed polyketide biosynthesis of lankacidin. Three ketoreductase domains (lkcC-KR, lkcF-KR1, and lkcF-KR2) were inactivated by in-frame deletion and site-directed mutagenesis of their active sites. The mutants ceased or diminished lankacidin production, indicating that the three KR domains are functional in lankacidin biosynthesis. However, all of the KR mutants failed to accumulate the expected unreduced metabolites. Mutational analysis of two tandemly aligned acyl carrier protein domains (lkcC-ACP1 and lkcC-ACP2) revealed that either ACP is sufficient for lankacidin production. Disruption and complementation experiments on three unique genes/domain (lkcD for acyltransferase, lkcB for dehydratase, and lkcC-MT for a C-methyltransferase domain) suggested that their gene products function iteratively during lankacidin biosynthesis.
authors: Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Japan.
authors: Satoshi
authors: S
authors: Tatsuno
authors: Kenji
authors: K
authors: Arakawa
authors: Haruyasu
authors: H
authors: Kinashi
mesh_terms: D000217:Acyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D004252:DNA Mutational Analysis / Q000379:methods*; D018942:Macrolides / Q000378:metabolism*; D008780:Methyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*
chemical_list: D018942:Macrolides; C008250:lankacidins; D010088:Oxidoreductases; D008780:Methyltransferases; D000217:Acyltransferases