Nakamoto R K, Ketchum C J, Kuo P H, Peskova Y B, Al-Shawi M K
Department of Molecular Physiology and Biological Physics, University of Virginia, P.O. Box 10011, Charlottesville, VA 22906-0011, USA.
Biochim Biophys Acta. 2000 May 31;1458(2-3):289-99. doi: 10.1016/s0005-2728(00)00081-5.
Rotation of the F(0)F(1) ATP synthase gamma subunit drives each of the three catalytic sites through their reaction pathways. The enzyme completes three cycles and synthesizes or hydrolyzes three ATP for each 360 degrees rotation of the gamma subunit. Mutagenesis studies have yielded considerable information on the roles of interactions between the rotor gamma subunit and the catalytic beta subunits. Amino acid substitutions, such as replacement of the conserved gammaMet-23 by Lys, cause altered interactions between gamma and beta subunits that have dramatic effects on the transition state of the steady state ATP synthesis and hydrolysis reactions. The mutations also perturb transmission of specific conformational information between subunits which is important for efficient conversion of energy between rotation and catalysis, and render the coupling between catalysis and transport inefficient. Amino acid replacements in the transport domain also affect the steady state catalytic transition state indicating that rotation is involved in coupling to transport.
F(0)F(1) ATP合酶γ亚基的旋转驱动三个催化位点逐一通过其反应途径。每旋转360度，该酶完成三个循环并合成或水解三个ATP。诱变研究已得出大量有关转子γ亚基与催化β亚基之间相互作用作用的信息。氨基酸取代，例如将保守的γMet-23替换为赖氨酸，会导致γ亚基和β亚基之间的相互作用发生改变，这对稳态ATP合成和水解反应的过渡态具有显著影响。这些突变还扰乱了亚基之间特定构象信息的传递，这对于能量在旋转和催化之间的有效转换很重要，并使催化与转运之间的偶联效率低下。转运结构域中的氨基酸替换也会影响稳态催化过渡态，表明旋转参与了与转运的偶联。
