Effect of epsilon subunit on the rotation of thermophilic Bacillus F1-ATPase.
F(1)-ATPase is an ATP-driven motor in which gammaepsilon rotates in the alpha(3)beta(3)-cylinder. It is attenuated by MgADP inhibition and by the epsilon subunit in an inhibitory form. The non-inhibitory form of epsilon subunit of thermophilic Bacillus PS3 F(1)-ATPase is stabilized by ATP-binding with micromolar K(d) at 25 degrees C. Here, we show that at [ATP]>2 microM, epsilon does not affect rotation of PS3 F(1)-ATPase but, at 200 nM ATP, epsilon prolongs the pause of rotation caused by MgADP inhibition while the frequency of the pause is unchanged. It appears that epsilon undergoes reversible transition to the inhibitory form at [ATP] below K(d).
Tsumuraya
Masato
M
Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259, Yokohama 226-8503, Japan.
Furuike
Shou
S
Adachi
Kengo
K
Kinosita
Kazuhiko
K
Yoshida
Masasuke
M
D000244:Adenosine Diphosphate / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D001407:Bacillus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D025243:Bacterial Proton-Translocating ATPases / Q000737:chemistry* / Q000378:metabolism; D020134:Catalytic Domain / Q000502:physiology; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000378:metabolism
D001426:Bacterial Proteins; D020409:Molecular Motor Proteins; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D025243:Bacterial Proton-Translocating ATPases