Reduction and Methyl Transfer Kinetics of the Alpha Subunit from Acetyl-Coenzyme A Synthase

Journal Article · Wed Jan 15 04:00:00 EST 2003 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja028442t· OSTI ID:826207

Tan, Xiangshi ^[1]; Sewell, Christopher; Yang, Qingwu; Lindahl, Paul A

---

1. Texas A&M University

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
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 2 Vol. 125
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ACETYL-COA SYNTHASE
ALPHA SUBUNIT
BIOCHEMICAL REACTION KINETICS
CATALYSIS
COENZYMES
IRON SULFIDES
METHYLATION
REDUCTION
STOPPED-FLOW
SYNTHESIS