Proposed mechanism for the condensation reaction of citrate synthase: 1.9-A structure of the ternary complex with oxaloacetate and carboxymethyl coenzyme A.Karpusas, M., Branchaud, B., Remington, S.J.
(1990) Biochemistry 29: 2213-2219
- PubMed: 2337600
- Primary Citation of Related Structures:
- PubMed Abstract:
- Crystal Structure Analysis of the Tetragonal Crystal Form and Preliminary Molecular Model of Pig-Heart Citrate Synthase
Wiegand, G.,Kukla, D.,Scholze, H.,Jones, T.A.,Huber, R.
(1979) Eur.J.Biochem. 93: 41
- Crystallographic Refinement and Atomic Models of Two Different Forms of Citrate Synthase at 2.7 And 1.7 Angstroms Resolution
Remington, S.,Wiegand, G.,Huber, R.
(1982) J.Mol.Biol. 158: 111
- Primary Structure of Porcine Heart Citrate Synthase
Bloxham, D.P.,Parmelee, D.C.,Kumar, S.,Wade, R.D.,Ericsson, L.H.,Neurath, H.,Walsh, K.A.,Titani, K.
(1981) Proc.Natl.Acad.Sci.USA 78: 5381
- Crystal Structure Analysis and Molecular Model of a Complex of Citrate Synthase with Oxaloacetate and S-Acetonyl-Coenzymea
Wiegand, G.,Remington, S.,Deisenhofer, J.,Huber, R.
(1984) J.Mol.Biol. 174: 205
The crystal structure of the ternary complex citrate synthase-oxaloacetate-carboxymethyl coenzyme A has been solved to a resolution of 1.9 A and refined to a conventional crystallographic R factor of 0.185. The structure resembles a proposed transiti ...
The crystal structure of the ternary complex citrate synthase-oxaloacetate-carboxymethyl coenzyme A has been solved to a resolution of 1.9 A and refined to a conventional crystallographic R factor of 0.185. The structure resembles a proposed transition state of the condensation reaction and suggests that the condensation reaction proceeds through a neutral enol rather than an enolate intermediate. A mechanism for the condensation reaction is proposed which involves the participation of three key catalytic groups (Asp 375, His 274, and His 320) in two distinct steps. The proposed mechanism invokes concerted general acid-base catalysis twice to explain both the energetics of the reaction and the experimentally observed inversion of stereochemistry at the attacking carbon atom.
Institute of Molecular Biology, University of Oregon, Eugene 97403.