Nishizaka Takayuki, Oiwa Kazuhiro, Noji Hiroyuki, Kimura Shigeki, Muneyuki Eiro, Yoshida Masasuke, Kinosita Kazuhiko
Kansai Advanced Research Center, Protein Biophysics Group, Iwaoka 588-2, Nishi-ku, Kobe 651-2492, Japan.
Nat Struct Mol Biol. 2004 Feb;11(2):142-8. doi: 10.1038/nsmb721. Epub 2004 Jan 18.
F(1)-ATPase is a rotary molecular motor in which unidirectional rotation of the central gamma subunit is powered by ATP hydrolysis in three catalytic sites arranged 120 degrees apart around gamma. To study how hydrolysis reactions produce mechanical rotation, we observed rotation under an optical microscope to see which of the three sites bound and released a fluorescent ATP analog. Assuming that the analog mimics authentic ATP, the following scheme emerges: (i) in the ATP-waiting state, one site, dictated by the orientation of gamma, is empty, whereas the other two bind a nucleotide; (ii) ATP binding to the empty site drives an approximately 80 degrees rotation of gamma; (iii) this triggers a reaction(s), hydrolysis and/or phosphate release, but not ADP release in the site that bound ATP one step earlier; (iv) completion of this reaction induces further approximately 40 degrees rotation.
F(1)-ATP酶是一种旋转分子马达，其中中央γ亚基的单向旋转由围绕γ亚基呈120度排列的三个催化位点处的ATP水解提供动力。为了研究水解反应如何产生机械旋转，我们在光学显微镜下观察旋转，以确定三个位点中的哪一个结合并释放了荧光ATP类似物。假设该类似物模拟真实的ATP，则出现以下模式：(i) 在ATP等待状态下，由γ亚基的取向决定的一个位点是空的，而另外两个位点结合一个核苷酸；(ii) ATP与空位点的结合驱动γ亚基旋转约80度；(iii) 这触发一个反应（水解和/或磷酸释放），但不是在一步之前结合ATP的位点释放ADP；(iv) 该反应的完成诱导进一步约40度的旋转。
