The 2-A crystal structure of 6-oxo camphor hydrolase. New structural diversity in the crotonase superfamily.
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Whittingham JL, Turkenburg JP, Verma CS, Walsh MA, Grogan G
The 2-A crystal structure of 6-oxo camphor hydrolase. New structural diversity in the crotonase superfamily.
J Biol Chem. 2003 Jan 17;278(3):1744-50. Epub 2002 Nov 5.
- PubMed ID
- 12421807 [ View in PubMed]
- Abstract
6-Oxo camphor hydrolase (OCH) is an enzyme of the crotonase superfamily that catalyzes carbon-carbon bond cleavage in bicyclic beta-diketones via a retro-Claisen reaction (Grogan, G., Roberts, G. A., Bougioukou, D., Turner, N. J., and Flitsch, S. L. (2001) J. Biol. Chem. 276, 12565-12572). The native structure of OCH has been solved at 2.0-A resolution with selenomethionine multiple wave anomalous dispersion and refined to a final R(free) of 19.0. The structure of OCH consists of a dimer of trimers that resembles the "parent" enzyme of the superfamily, enoyl-CoA hydratase. In contrast to enoyl-CoA hydratase, however, two octahedrally coordinated sodium atoms are found at the 3-fold axis of the hexamer of OCH, and the C-terminal helix of OCH does not form a discrete domain. Models of the substrate, 6-oxo camphor, and a proposed enolate intermediate in the putative active site suggest possible mechanistic roles for Glu-244, Asp-154, His-122, His-45, and His-145.