Reaction: bornane-2,6-dione + H2O = [(1S)-4-hydroxy-2,2,3-trimethylcyclopent-3-enyl]acetate
For diagram of reaction click here and mechanism click here.
Glossary: α-campholonate = (4-hydroxy-2,2,3-trimethylcyclopent-3-enyl)acetate (enol form) = (2,2,3-trimethyl-4-oxocyclopentyl)acetate (keto form)
Other name(s): OCH; camK (gene name)
Systematic name: bornane-2,6-dione hydrolase
Comments: Isolated from Rhodococcus sp. The bornane ring system is cleaved by a retro-Claisen reaction to give the enol of α-campholonate. When separate from the enzyme the enol is tautomerised to the keto form as a 6:1 mixture of [(1S,3R)-2,2,3-trimethyl-4-oxocyclopentyl]acetate and [(1S,3S)-2,2,3-trimethyl-4-oxocyclopentyl]acetate.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:
References:
1. Grogan, G., Roberts, G.A., Bougioukou, D., Turner, N.J. and Flitsch, S.L. The desymmetrization of bicyclic β-diketones by an enzymatic retro-Claisen reaction. A new reaction of the crotonase superfamily. J. Biol. Chem. 276 (2001) 12565-12572. [PMID: 11278926]
2. Whittingham, J.L., Turkenburg, J.P., Verma, C.S., Walsh, M.A. and Grogan, G. The 2-Å crystal structure of 6-oxo camphor hydrolase. New structural diversity in the crotonase superfamily. J. Biol. Chem. 278 (2003) 1744-1750. [PMID: 12421807]
3. Leonard, P.M. and Grogan, G. Structure of 6-oxo camphor hydrolase H122A mutant bound to its natural product, (2S,4S)-α-campholinic acid: mutant structure suggests an atypical mode of transition state binding for a crotonase homolog. J. Biol. Chem. 279 (2004) 31312-31317. [PMID: 15138275]