1w3v

From Proteopedia

Revision as of 15:19, 5 November 2007

ISOPENICILLIN N SYNTHASE D-(L-A-AMINOADIPOYL)-(3R)-METHYL-L-CYSTEINE D-A-HYDROXYISOVALERYL ESTER COMPLEX (ANAEROBIC)

Overview

Isopenicillin N synthase (IPNS) is a non-heme iron(ii)-dependent oxidase, that is central to penicillin biosynthesis. Herein, we report mechanistic, studies of the IPNS reaction in the crystalline state, using the substrate, analogue delta-(L-alpha-aminoadipoyl)-(3R)-methyl-L-cysteine, D-alpha-hydroxyisovaleryl ester (AmCOV) to probe the early stages of the, catalytic cycle. The X-ray crystal structure of the anaerobic, IPNS:Fe(II):AmCOV complex was solved to 1.40 A resolution, and it reveals, several subtle differences in the active site relative to the complex of, the enzyme with its natural substrate. The crystalline IPNS:Fe(II):AmCOV, complex was then exposed to oxygen gas at high pressure; this brought, about reaction to give what appears to be a hydroxymethyl/ene-thiol, product. A mechanism for this reaction is proposed. These results offer, further insight into the delicate interplay of steric and electronic, effects in the IPNS active site and the mechanistic intricacies of this, remarkable enzyme.

About this Structure

1W3V is a Single protein structure of sequence from Emericella nidulans with FE2 and MDZ as ligands. Active as Isopenicillin-N synthase, with EC number 1.21.3.1 Structure known Active Site: AC1. Full crystallographic information is available from OCA.

Reference

Unexpected oxidation of a depsipeptide substrate analogue in crystalline isopenicillin N synthase., Daruzzaman A, Clifton IJ, Adlington RM, Baldwin JE, Rutledge PJ, Chembiochem. 2006 Feb;7(2):351-8. PMID:16444759

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