title: Conformational dynamics monitored by His-179 and His-200 of isolated thermophilic F1-ATPase beta subunit which reside at the entrance of the 'conical tunnel' in holoenzyme.
abstract: When monitored by 1H NMR at various pH values, most of the C-2 proton signals from 12 His residues of the isolated beta subunit of thermophilic F1-ATPase (TF1) could be separately observed. Two of them were assigned to His-179 and His-200 which reside at the entrance of a 'conical tunnel' to reach catalytic site in the crystal structure of F1-ATPase. His-200 gave doublet, suggesting that this region is not a rigid alpha-helix in the isolated beta subunit. The binding of Mg.AMP-PNP changed the chemical shifts of His-179 and His-200 significantly. Although His-119 located at the opposite side of the conical tunnel was not affected by the nucleotide-binding, it contributed to the stability of beta subunit and the efficiency of the catalysis of the holoenzyme.
mesh_terms: D001407:Bacillus / Q000201:enzymology; D001665:Binding Sites; D002384:Catalysis; D006639:Histidine / Q000737:chemistry*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D006180:Proton-Translocating ATPases / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D006639:Histidine; D006180:Proton-Translocating ATPases