Monacolin J acid methylbutanoyltransferase

UniProtKB accession:  Q9Y7D1

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UniProtKB description:  Monacolin J acid methylbutanoyltransferase; part of the gene cluster that mediates the biosynthesis of lovastatin (also known as mevinolin, mevacor or monacolin K), a hypolipidemic inhibitor of (3S)-hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase (HMGR) (PubMed:10334994, PubMed:12929390, PubMed:21495633). The first step in the biosynthesis of lovastatin is the production of dihydromonacolin L acid by the lovastatin nonaketide synthase lovB and the trans-acting enoyl reductase lovC via condensation of one acetyl-CoA unit and 8 malonyl-CoA units (PubMed:10334994, PubMed:10381407, PubMed:19900898, PubMed:22733743). Dihydromonacolin L acid is released from lovB by the thioesterase lovG (PubMed:23653178). Next, dihydromonacolin L acid is oxidized by the dihydromonacolin L monooxygenase lovA twice to form monacolin J acid (PubMed:12929390, PubMed:21495633). The 2-methylbutyrate moiety of lovastatin is synthesized by the lovastatin diketide synthase lovF via condensation of one acetyl-CoA unit and one malonyl-CoA unit (PubMed:19530726, PubMed:21069965). Finally, the covalent attachment of this moiety to monacolin J acid is catalyzed by the transesterase lovD to yield lovastatin (PubMed:10334994, PubMed:17113998, PubMed:18988191, PubMed:19875080, PubMed:24727900). LovD has broad substrate specificity and can also convert monacolin J to simvastatin using alpha-dimethylbutanoyl-S-methyl-3-mercaptopropionate (DMB-S-MMP) as the thioester acyl donor, and can also catalyze the reverse reaction and function as hydrolase in vitro (PubMed:19875080). LovD has much higher activity with LovF-bound 2-methylbutanoate than with free diketide substrates (PubMed:21069965).