2vbp
Isopenicillin N synthase with substrate analogue L,L,L-ACAB (unexposed)
Structural highlights
FunctionIPNA_EMENI Isopenicillin N synthase; part of the gene cluster that mediates the biosynthesis of penicillin, the world's most important antibiotic (PubMed:3319778, PubMed:11755401). IpnA catalyzes the cyclization of the tripeptide N-[(5S)-5-amino-5-carboxypentanoyl]-L-cysteinyl-D-valine (LLD-ACV or ACV) to form isopenicillin N (IPN) that contains the beta-lactam nucleus (PubMed:3319778, PubMed:11755401, PubMed:28703303). The penicillin biosynthesis occurs via 3 enzymatic steps, the first corresponding to the production of the tripeptide N-[(5S)-5-amino-5-carboxypentanoyl]-L-cysteinyl-D-valine (LLD-ACV or ACV) by the NRPS acvA. The tripeptide ACV is then cyclized to isopenicillin N (IPN) by the isopenicillin N synthase ipnA that forms the beta-lactam nucleus. Finally, the alpha-aminoadipyl side chain is exchanged for phenylacetic acid by the isopenicillin N acyltransferase penDE to yield penicillin in the peroxisomal matrix (By similarity).[UniProtKB:P08703][1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedIsopenicillin N synthase (IPNS) is a non-heme iron(II) oxidase which catalyses the biosynthesis of isopenicillin N (IPN) from the tripeptide delta-l-alpha-aminoadipoyl-l-cysteinyl-d-valine (lld-ACV). Herein we report crystallographic studies to investigate the binding of a truncated lll-substrate in the active site of IPNS. Two epimeric tripeptides have been prepared by solution phase peptide synthesis and crystallised with the enzyme. delta-l-alpha-Aminoadipoyl-l-cysteinyl-d-2-amino-3,3-dideuteriobutyrate (lld-ACd(2)Ab) has the same configuration as the natural substrate lld-ACV at each of its three stereocentres; its epimer delta-l-alpha-aminoadipoyl-l-cysteinyl-l-2-amino-3,3-dideuteriobutyrate (lll-ACd(2)Ab) has the opposite configuration at its third amino acid. lll-ACV has previously been shown to inhibit IPNS turnover of its substrate lld-ACV; the all-protiated tripeptide delta-l-alpha-aminoadipoyl-l-cysteinyl-d-2-aminobutyrate (lld-ACAb) is a substrate for IPNS, being turned over to a mixture of penam and cepham products. Comparisons between the crystal structures of the IPNS:Fe(II):lld-ACd(2)Ab and IPNS:Fe(II):lll-ACd(2)Ab complexes offer a possible rationale for the previously observed inhibitory effects of lll-ACV on IPNS activity. Crystallographic studies on the binding of selectively deuterated LLD- and LLL-substrate epimers by isopenicillin N synthase.,Ge W, Clifton IJ, Stok JE, Adlington RM, Baldwin JE, Rutledge PJ Biochem Biophys Res Commun. 2010 Aug 6;398(4):659-64. Epub 2010 Jul 13. PMID:20603104[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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