1o8u
From Proteopedia
The 2 Angstrom Structure of 6-Oxo Camphor Hydrolase: New Structural Diversity in the Crotonase Superfamily
Structural highlights
FunctionCAMK_RHOSO Catalyzes the carbon-carbon bond cleavage of the bicyclic beta-diketone 6-oxocamphor via a retro-Claisen reaction to yield the optically active (2R,4S)-beta-campholinic acid. It is also able to cleave 2,2-disubstituted cyclohexa-1,3-diones such as 2-methyl-2-propylcyclohexa-1,3-dione and 2-methyl-2-butylcyclohexa-1,3-dione which result in racemic keto acid products. Transformations of the bicyclic diketone substrates bicyclo[2.2.1]heptane 2,6-dione and bicyclo[2.2.2]octane-2,6-dione yield (S)-keto acid products.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed6-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. The 2-A crystal structure of 6-oxo camphor hydrolase. New structural diversity in the crotonase superfamily.,Whittingham JL, Turkenburg JP, Verma CS, Walsh MA, Grogan G J Biol Chem. 2003 Jan 17;278(3):1744-50. Epub 2002 Nov 5. PMID:12421807[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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