Post-translational enzyme modification by the phosphopantetheinyl transferase is required for lysine and penicillin biosynthesis but not for roquefortine or fatty acid formation in Penicillium chrysogenum

摘要

pNRPSs (non-ribosomal peptide synthetases) and PKSs (polyketide synthases) require post-translational phosphopantetheinylation to become active. This reaction is catalysed by a PPTase (4′-phosphopantetheinyl transferase). The ippt/i gene of iPenicillium chrysogenum/i, encoding a protein that shares 50% similarity with the stand-alone large PPTases, has been cloned. This gene is present as a single copy in the genome of the wild-type and high-penicillin-producing strains (containing multiple copies of the penicillin gene cluster). Amplification of the ippt/i gene produced increases in isopenicillin N and benzylpenicillin biosynthesis. A PPTase-defective mutant (Wis54-PPTsup?/sup) was obtained. It required lysine and lacked pigment and penicillin production, but it still synthesized normal levels of roquefortine. The biosynthesis of roquefortine does not appear to involve PPTase-mediated modification of the synthesizing enzymes. The PPTsup?/sup mutant did not require fatty acids, which indicates that activation of the fatty acid synthase is performed by a different PPTase. Complementation of Wis54-PPTsup?/sup with the ippt/i gene restored lysine biosynthesis, pigmentation and penicillin production, which demonstrates the wide range of processes controlled by this gene./p