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Conformational dynamics monitored by His‐179 and His‐200 of isolated thermophilic F 1 ‐ATPase β subunit which reside at the entrance of the ‘conical tunnel’ in holoenzyme
Author(s) -
Tozawa Kaeko,
Sekino Nobuaki,
Soga Masanobu,
Yagi Hiromasa,
Yoshida Masasuke,
Akutsu Hideo
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)01276-2
Subject(s) - protein subunit , thermophile , conical surface , atpase , chemistry , helix (gastropod) , crystallography , stereochemistry , biophysics , materials science , biochemistry , biology , enzyme , ecology , snail , composite material , gene
When monitored by 1 H NMR at various pH values, most of the C‐2 proton signals from 12 His residues of the isolated β subunit of thermophilic F 1 ‐ATPase (TF 1 ) could be separately observed. Two of them were assigned to His‐179 and His‐200 which reside at the entrance of a ‘conial tunnel’ to reach catalytic site in the crystal structure of F 1 ‐ATPase. His‐200 gave doublet, suggesting that this region is not a rigid α‐helix in the isolated β 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 β subunit and the efficiency of the catalysis of the holoenzyme.