Reduction and Methyl Transfer Kinetics of the Alpha Subunit from Acetyl-Coenzyme A Synthase
OAK-B135 Stopped-flow was used to evaluate the methylation and reduction kinetics of the isolated alpha subunit of acetyl-Coenzyme A synthase from Moorella thermoacetica. This catalytically active subunit contains a novel Ni-X-Fe4S4 cluster and a putative unidentified n =2 redox site called D. The D-site must be reduced for a methyl group to transfer from a corrinoid-iron-sulfur protein, a key step in the catalytic synthesis of acetyl-CoA. The Fe4S4 component of this cluster is also redox active, raising the possibility that it is the D-site or a portion thereof. Results presented demonstrate that the D-site reduces far faster than the Fe4S4 component, effectively eliminating this possibility. Rather, this component may alter catalytically important properties of the Ni center. The D-site is reduced through a pathway that probably does not involve the Fe4S4 component of this active-site cluster.
- Research Organization:
- Texas A& M University, College Station, TX (US)
- Sponsoring Organization:
- (US)
- DOE Contract Number:
- FG03-01ER15177
- OSTI ID:
- 826207
- Report Number(s):
- DOE/ER/15177-1; TRN: US200427%%2
- Journal Information:
- Journal of the American Chemical Society, Vol. 125, Issue 2; Other Information: Printed in the Journal of the American Chemical Society, Volume 125, No.2; DOI 10.1021/ja028442t; PBD: 15 Jan 2003
- Country of Publication:
- United States
- Language:
- English
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