Structural Basis for Cyclopropanation by a Unique Enoyl-Acyl Carrier Protein Reductase.Khare, D., Hale, W.A., Tripathi, A., Gu, L., Sherman, D.H., Gerwick, W.H., Hakansson, K., Smith, J.L.
(2015) Structure 23: 2213-2223
- PubMed: 26526850
- DOI: https://doi.org/10.1016/j.str.2015.09.013
- Primary Citation of Related Structures:
5DOV, 5DOZ, 5DP1, 5DP2
- PubMed Abstract:
The natural product curacin A, a potent anticancer agent, contains a rare cyclopropane group. The five enzymes for cyclopropane biosynthesis are highly similar to enzymes that generate a vinyl chloride moiety in the jamaicamide natural product. The structural biology of this remarkable catalytic adaptability is probed with high-resolution crystal structures of the curacin cyclopropanase (CurF ER), an in vitro enoyl reductase (JamJ ER), and a canonical curacin enoyl reductase (CurK ER). The JamJ and CurK ERs catalyze NADPH-dependent double bond reductions typical of enoyl reductases (ERs) of the medium-chain dehydrogenase reductase (MDR) superfamily. Cyclopropane formation by CurF ER is specified by a short loop which, when transplanted to JamJ ER, confers cyclopropanase activity on the chimeric enzyme. Detection of an adduct of NADPH with the model substrate crotonyl-CoA provides indirect support for a recent proposal of a C2-ene intermediate on the reaction pathway of MDR enoyl-thioester reductases.
Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.