Delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine synthetase from Aspergillus nidulans. Molecular characterization of the acvA gene encoding the first enzyme of the penicillin biosynthetic pathway.

摘要: The Aspergillus nidulans gene (acvA) encoding the first catalytic steps of penicillin biosynthesis that result in formation delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine (ACV), has been positively identified by matching a 15-amino acid segment sequence obtained from an internal CNBr fragment purified amino-terminally blocked protein with predicted DNA sequence. acvA is transcribed opposite orientation to ipnA (encoding isopenicillin N synthetase), intergenic region 872 nucleotides. completely sequenced at nucleotide level and found encode 3,770 amino acids (molecular mass, 422,486 Da). Both fast liquid chromatography native gel estimates molecular mass are consistent this weight. enzyme was as glycoprotein means affinity blotting concanavalin A. No evidence for presence introns within found. derived ACV synthetase (ACVS) contains three homologous regions about 585 residues, each which displays areas similarity (i) adenylate-forming enzymes such parsley 4-coumarate-CoA ligase firefly luciferase (ii) several multienzyme peptide synthetases, including bacterial gramicidin S 1 tyrocidine 1. Despite these similarities, conserved cysteine residues latter synthetases thought be essential thiotemplate mechanism have not detected ACVS These observations, together occurrence putative 4'-phosphopantetheine-attachment sites thioesterase site, discussed reference reaction leading production tripeptide. We speculate corresponds functional domain recognizes one substrate acids.