Structure of acyl carrier protein bound to FabI, the FASII enoyl reductase from Escherichia coli.
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Rafi S, Novichenok P, Kolappan S, Zhang X, Stratton CF, Rawat R, Kisker C, Simmerling C, Tonge PJ
Structure of acyl carrier protein bound to FabI, the FASII enoyl reductase from Escherichia coli.
J Biol Chem. 2006 Dec 22;281(51):39285-93. Epub 2006 Sep 29.
- PubMed ID
- 17012233 [ View in PubMed]
- Abstract
Acyl carrier proteins play a central role in metabolism by transporting substrates in a wide variety of pathways including the biosynthesis of fatty acids and polyketides. However, despite their importance, there is a paucity of direct structural information concerning the interaction of ACPs with enzymes in these pathways. Here we report the structure of an acyl-ACP substrate bound to the Escherichia coli fatty acid biosynthesis enoyl reductase enzyme (FabI), based on a combination of x-ray crystallography and molecular dynamics simulation. The structural data are in agreement with kinetic studies on wild-type and mutant FabIs, and reveal that the complex is primarily stabilized by interactions between acidic residues in the ACP helix alpha2 and a patch of basic residues adjacent to the FabI substrate-binding loop. Unexpectedly, the acyl-pantetheine thioester carbonyl is not hydrogen-bonded to Tyr(156), a conserved component of the short chain alcohol dehydrogenase/reductase superfamily active site triad. FabI is a proven target for drug discovery and the present structure provides insight into the molecular determinants that regulate the interaction of ACPs with target proteins.