ISSN:
1573-6881
Keywords:
Oxidative phosphorylation
;
ATP synthase
;
F1-ATPase
;
catalytic transition state
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Physics
Notes:
Abstract The catalytic transition state of ATP synthase has been characterized and modeled by combined use of (1) Mg-ADP–fluoroaluminate, Mg-ADP–fluoroscandium, and corresponding Mg-IDP–fluorometals as transition-state analogs; (2) fluorescence signals of β-Trp331 and β-Trp148 as optical probes to assess formation of the transition state; (3) mutations of critical catalytic residues to determine side-chain ligands required to stabilize the transition state. Rate acceleration by positive catalytic site cooperativity is explained as due to mobility of α-Arg376, acting as an “arginine finger” residue, which interacts with nucleotide specifically at the transition state step of catalysis, not with Mg-ATP- or Mg-ADP-bound ground states. We speculate that formation and collapse of the transition state may engender catalytic site α/β subunit-interface conformational movement, which is linked to γ-subunit rotation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1005625326721
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