Role of αPhe-291 residue in the phosphate-binding subdomain of catalytic sites of Escherichia coli ATP synthase
| Autor: | Johnny J. Grindstaff, Laura Brudecki, Zulfiqar Ahmad |
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| Rok vydání: | 2008 |
| Předmět: |
Azides
Phenylalanine ATPase Biophysics Crystallography X-Ray medicine.disease_cause Biochemistry Phosphates Residue (chemistry) ATP hydrolysis ATP synthase gamma subunit Catalytic Domain Escherichia coli medicine Enzyme Inhibitors Phosphorylation Binding site Molecular Biology Binding Sites Base Sequence biology ATP synthase Hydrolysis Fluorine Molecular biology ATP Synthetase Complexes Adenosine Diphosphate 4-Chloro-7-nitrobenzofurazan Mutation biology.protein Tyrosine Aluminum |
| Zdroj: | Archives of Biochemistry and Biophysics. 471:168-175 |
| ISSN: | 0003-9861 |
| Popis: | The role of alphaPhe-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 betaR246 residue. Herein, we show that mutations alphaF291D and alphaF291E 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 approximately 75%, although reaction still occurred at residue betaTyr-297, proximal to alphaPhe-291 in the phosphate-binding pocket. Inhibition characteristics supported the conclusion that NBD-Cl reacts in betaE (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 alphaPhe-291 with phosphate during ATP hydrolysis or synthesis may be distinct. |
| Databáze: | OpenAIRE |
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