Hossain Mohammad Delawar, Furuike Shou, Onoue Yasuhiro, Adachi Kengo, Yoshida Masasuke, Kinosita Kazuhiko
Department of Physics, Faculty of Science and Engineering, Waseda University, Shinjuku-ku, Tokyo, Japan.
Biochim Biophys Acta. 2010 Apr;1797(4):435-42. doi: 10.1016/j.bbabio.2009.12.018. Epub 2010 Jan 4.
F(1)-ATPase is a rotary molecular motor in which the gamma subunit rotates inside the cylinder made of alpha(3)beta(3) subunits. We have studied the effects of sodium dodecyl sulfate (SDS) on the rotational and ATP hydrolysis activities of F(1)-ATPase. Bulk hydrolysis activity at various SDS concentrations was examined at 2mM ATP. Maximal stimulation was obtained at 0.003% (w/v) SDS, the initial (least inhibited) activity being about 1.4 times and the steady-state activity 3-4 times the values in the absence of SDS. Rotation rates observed with a 40-nm gold bead or a 0.29-mum bead duplex as well as the torque were unaffected by the presence of 0.003% SDS. The fraction of beads that rotated, in contrast, tended to increase in the presence of SDS. SDS seems to bring inactive F(1) molecules into an active form but it does not alter or enhance the function of already active F(1) molecules significantly.
F(1)-ATP酶是一种旋转分子马达，其中γ亚基在由α(3)β(3)亚基组成的圆柱体内旋转。我们研究了十二烷基硫酸钠（SDS）对F(1)-ATP酶旋转和ATP水解活性的影响。在2mM ATP条件下检测了不同SDS浓度下的总体水解活性。在0.003%（w/v）SDS时获得最大刺激，初始（抑制最小）活性约为无SDS时的1.4倍，稳态活性为无SDS时的三到四倍。用40纳米金珠或0.29微米珠双链体观察到的旋转速率以及扭矩不受0.003% SDS存在的影响。相比之下，旋转珠子的比例在SDS存在时倾向于增加。SDS似乎使无活性的F(1)分子转变为活性形式，但它不会显著改变或增强已具有活性的F(1)分子的功能。
