1qjf
From Proteopedia
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'''ISOPENICILLIN N SYNTHASE FROM ASPERGILLUS NIDULANS (MONOCYCLIC SULFOXIDE-FE COMPLEX)''' | '''ISOPENICILLIN N SYNTHASE FROM ASPERGILLUS NIDULANS (MONOCYCLIC SULFOXIDE-FE COMPLEX)''' | ||
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[[Category: Roach, P L.]] | [[Category: Roach, P L.]] | ||
[[Category: Rutledge, P J.]] | [[Category: Rutledge, P J.]] | ||
| - | [[Category: | + | [[Category: B-lactam antibiotic]] |
| - | [[Category: | + | [[Category: Monocyclic intermediate]] |
| - | [[Category: | + | [[Category: Oxygenase]] |
| - | [[Category: | + | [[Category: Penicillin biosynthesis]] |
| - | [[Category: | + | [[Category: Sulfoxide]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 06:20:58 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 03:20, 3 May 2008
ISOPENICILLIN N SYNTHASE FROM ASPERGILLUS NIDULANS (MONOCYCLIC SULFOXIDE-FE COMPLEX)
Overview
Isopenicillin N synthase (IPNS), a non-haem iron-dependent oxidase, catalyses the biosynthesis of isopenicillin N (IPN), the precursor of all penicillins and cephalosporins. The key steps in this reaction are the two iron-dioxygen-mediated ring closures of the tripeptide delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-valine (ACV). It has been proposed that the four-membered beta-lactam ring forms initially, associated with a highly oxidized iron(iv)-oxo (ferryl) moiety, which subsequently mediates closure of the five-membered thiazolidine ring. Here we describe observation of the IPNS reaction in crystals by X-ray crystallography. IPNS Fe2+ substrate crystals were grown anaerobically, exposed to high pressures of oxygen to promote reaction and frozen, and their structures were elucidated by X-ray diffraction. Using the natural substrate ACV, this resulted in the IPNS x Fe2+ x IPN product complex. With the substrate analogue, delta-(L-alpha-aminoadipoyl)-L-cysteinyl-L-S-methylcysteine (ACmC) in the crystal, the reaction cycle was interrupted at the monocyclic stage. These mono- and bicyclic structures support our hypothesis of a two-stage reaction sequence leading to penicillin. Furthermore, the formation of a monocyclic sulphoxide product from ACmC is most simply explained by the interception of a high-valency iron-oxo species.
About this Structure
1QJF is a Single protein structure of sequence from Emericella nidulans. Full crystallographic information is available from OCA.
Reference
The reaction cycle of isopenicillin N synthase observed by X-ray diffraction., Burzlaff NI, Rutledge PJ, Clifton IJ, Hensgens CM, Pickford M, Adlington RM, Roach PL, Baldwin JE, Nature. 1999 Oct 14;401(6754):721-4. PMID:10537113 Page seeded by OCA on Sat May 3 06:20:58 2008
