View source for 6cts

[[Image:6cts.gif|left|200px]]

 {{Structure
|PDB= 6cts |SIZE=350|CAPTION= <scene name='initialview01'>6cts</scene>, resolution 2.5&Aring;
|SITE= 
|LIGAND= <scene name='pdbligand=CIC:CITRYL-THIOETHER-COENZYME *A'>CIC</scene>
|ACTIVITY= [http://en.wikipedia.org/wiki/Citrate_(Si)-synthase Citrate (Si)-synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.3.1 2.3.3.1] 
|GENE= 
}}

'''PROPOSED MECHANISM FOR THE CONDENSATION REACTION OF CITRATE SYNTHASE. 1.9-ANGSTROMS STRUCTURE OF THE TERNARY COMPLEX WITH OXALOACETATE AND CARBOXYMETHYL COENZYME A'''


==Overview==
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.

==About this Structure==
6CTS is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6CTS OCA]. 

==Reference==
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 SJ, Biochemistry. 1990 Mar 6;29(9):2213-9. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/2337600 2337600]
[[Category: Citrate (Si)-synthase]]
[[Category: Gallus gallus]]
[[Category: Single protein]]
[[Category: Branchaud, B.]]
[[Category: Karpusas, M.]]
[[Category: Remington, S J.]]
[[Category: CIC]]
[[Category: oxo-acid-lyase]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 19:13:22 2008''