Download MendeleyCrystallographic Studies on the Binding of Selectively Deuterated Lld- and Lll-Substrate Epimers by Isopenicillin N Synthase.
Ge, W., Clifton, I.J., Stok, J.E., Adlington, R.M., Baldwin, J.E., Rutledge, P.J.(2010) Biochem Biophys Res Commun 398: 659
- PubMed: 20603104
- DOI: https://doi.org/10.1016/j.bbrc.2010.06.129
- Primary Citation of Related Structures:
2VBP, 2WO7 - PubMed Abstract:
Isopenicillin 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.
Organizational Affiliation:
Chemistry Research Laboratory, University of Oxford, Mansfield Rd., Oxford OX1 3TA, UK.
