Structure of isopenicillin N synthase complexed with substrate and the mechanism of penicillin formation.Roach, P.L., Clifton, I.J., Hensgens, C.M., Shibata, N., Schofield, C.J., Hajdu, J., Baldwin, J.E.
(1997) Nature 387: 827-830
- PubMed: 9194566
- DOI: 10.1038/42990
- Primary Citation of Related Structures:  1BLZ
- Also Cited By: 1HB1, 1HB2, 1HB3, 1HB4, 1OBN, 1OC1, 1ODM, 1ODN, 1QIQ, 1QJE, 1QJF, 1UZW, 2IVI, 2IVJ
- PubMed Abstract:
- Crystallization and Preliminary X-Ray Diffraction Studies on Recombinant Isopenicillin N Synthase from Aspergillus Nidulans
Roach, P.L.,Schofield, C.J.,Baldwin, J.E.,Clifton, I.J.,Hajdu, J.
(1995) Protein Sci. 4: 1007
- Crystal Structure of Isopenicillin N Synthase is the First from a New Structural Family of Enzymes
Roach, P.L.,Clifton, I.J.,Fulop, V.,Harlos, K.,Barton, G.J.,Hajdu, J.,Andersson, I.,Schofield, C.J.,Baldwin, J.E.
(1995) Nature 375: 700
The biosynthesis of penicillin and cephalosporin antibiotics in microorganisms requires the formation of the bicyclic nucleus of penicillin. Isopenicillin N synthase (IPNS), a non-haem iron-dependent oxidase, catalyses the reaction of a tripeptide, d ...
The biosynthesis of penicillin and cephalosporin antibiotics in microorganisms requires the formation of the bicyclic nucleus of penicillin. Isopenicillin N synthase (IPNS), a non-haem iron-dependent oxidase, catalyses the reaction of a tripeptide, delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-valine (ACV), and dioxygen to form isopenicillin N and two water molecules. Mechanistic studies suggest the reaction is initiated by ligation of the substrate thiolate to the iron centre, and proceeds through an enzyme-bound monocyclic intermediate. Here we report the crystal structure of IPNS complexed to ferrous iron and ACV, determined to 1.3 A resolution. Based on the structure, we propose a mechanism for penicillin formation that involves ligation of ACV to the iron centre, creating a vacant iron coordination site into which dioxygen can bind. Subsequently, iron-dioxygen and iron-oxo species remove the requisite hydrogens from ACV without the direct assistance of protein residues. The crystal structure of the complex with the dioxygen analogue, NO and ACV bound to the active-site iron supports this hypothesis.
The Dyson Perrins Laboratory, University of Oxford, UK.