Role of αPhe-291 Residue in the Phosphate-Binding Subdomain of Catalytic Sites of Escherichia Coli ATP Synthase
Document Type
Article
Publication Date
3-15-2008
Description
The role of αPhe-291 residue in phosphate binding by Escherichia coli F1F0-ATP synthase was examined. X-ray structures of bovine mitochondrial enzyme suggest that this residue resides in close proximity to the conserved βR246 residue. Herein, we show that mutations αF291D and αF291E in E. coli reduce the ATPase activity of F1F0 membranes by 350-fold. Yet, significant oxidative phosphorylation activity is retained. In contrast to wild-type, ATPase activities of mutants were not inhibited by MgADP-azide, MgADP-fluoroaluminate, or MgADP-fluoroscandium. Whereas, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) inhibited wild-type ATPase essentially completely, ATPase in mutants was inhibited maximally by ∼75%, although reaction still occurred at residue βTyr-297, proximal to αPhe-291 in the phosphate-binding pocket. Inhibition characteristics supported the conclusion that NBD-Cl reacts in βE (empty) catalytic sites, as shown previously by X-ray structure analysis. Phosphate protected against NBD-Cl inhibition in wild-type but not in mutants. In addition, our data suggest that the interaction of αPhe-291 with phosphate during ATP hydrolysis or synthesis may be distinct.
Citation Information
Brudecki, Laura; Grindstaff, Johnny J.; and Ahmad, Zulfiqar. 2008. Role of αPhe-291 Residue in the Phosphate-Binding Subdomain of Catalytic Sites of Escherichia Coli ATP Synthase. Archives of Biochemistry and Biophysics. Vol.471(2). 168-175. https://doi.org/10.1016/j.abb.2008.01.013 PMID: 18242162 ISSN: 0003-9861