PROSITE documentation PDOC00165Isopenicillin N synthase signatures
Isopenicillin N synthase (EC 1.21.3.1) (IPNS) [1,2] is a key enzyme in the biosynthesis of penicillin and cephalosporin. In the presence of oxygen, it removes iron and ascorbate, four hydrogen atoms from L-(α-aminoadipyl)-L-cysteinyl-d-valine to form the azetidinone and thiazolidine rings of isopenicillin. IPNS is an enzyme of about 330 amino-acid residues. Two cysteines are conserved in fungal and bacterial IPNS sequences; these may be involved in iron-binding and/or substrate-binding.
Cephalosporium acremonium DAOCS/DACS [3] is a bifunctional enzyme involved in cephalosporin biosynthesis. The DAOCS domain, which is structurally related to IPNS, catalyzes the step from penicillin N to deacetoxy-cephalosporin C - used as a substrate by DACS to form deacetylcephalosporin C. Streptomyces clavuligerus possesses a monofunctional DAOCS enzyme (gene cefE) [4] also related to IPNS.
We derived two signature patterns for these enzymes, centered around the conserved cysteine residues.
Last update:May 2004 / Text revised.
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| 1 | Authors | Martin J.F. |
| Source | Trends Biotechnol. 5:306-308(1987). |
| 2 | Authors | Chen G. Shiffman D. Mevarech M. Aharonowitz Y. |
| Source | Trends Biotechnol. 8:105-111(1990). |
| 3 | Authors | Samson S.M. Dotzlaf J.E. Slisz M.L. Becker G.W. van Frank R.M. Veal L.E. Yeh W.K. Miller J.R. Queener S.W. Ingolia T.D. |
| Source | Bio/Technology 5:1207-1214(1987). |
| 4 | Authors | Kovacevic S. Weigel B.J. Tobin M.B. Ingolia T.D. Miller J.R. |
| Title | Cloning, characterization, and expression in Escherichia coli of the Streptomyces clavuligerus gene encoding deacetoxycephalosporin C synthetase. | |
| Source | J. Bacteriol. 171:754-760(1989). | |
| PubMed ID | 2644235 |
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