Stein W D, Läuger P
Department of Biological Chemistry, Hebrew University, Jerusalem, Israel.
Biophys J. 1990 Feb;57(2):255-67. doi: 10.1016/S0006-3495(90)82528-5.
We present an analysis of models based on current structural concepts of the F0F1 synthases, accounting for coupling between proton transport and ATP synthesis. It is assumed that each of the three alpha beta-subunits of the synthase can exist in three different conformational states E, Eo and E*. Proton translocation is coupled to cyclic interconversion of the conformations of the alpha beta-subunits. The conformational changes of these subunits are assumed to be coordinated so that all three interconvert simultaneously, in a rate-limiting transition. Binding and release of the ligands ATP, ADP, Pi, and protons are assumed to be equilibrium steps. In one family of models, interconversion of the alpha beta-subunits of F1 is coupled to the translocation event in F0 acting as a proton carrier. In a second family of models, protons combine with F0F1 and are translocated during the interconversion step in a chemiport. Kinetic tests involving the mutual effects of [ATP], [ADP], H+', and H+" are described, allowing us to make a distinction between the different models and submodels.
我们基于F0F1合酶当前的结构概念对模型进行了分析，解释了质子转运与ATP合成之间的偶联关系。假定合酶的三个αβ亚基中的每一个都可以存在于三种不同的构象状态E、Eo和E*。质子易位与αβ亚基构象的循环相互转化偶联。假定这些亚基的构象变化是协同的，以便所有三个亚基在限速转变中同时相互转化。配体ATP、ADP、Pi和质子的结合与释放被假定为平衡步骤。在一类模型中，F1的αβ亚基的相互转化与作为质子载体的F0中的易位事件偶联。在另一类模型中，质子与F0F1结合并在化学转运体的相互转化步骤中发生易位。描述了涉及[ATP]、[ADP]、H+'和H+"相互作用的动力学测试，这使我们能够区分不同的模型和子模型。
