Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Darlinghurst, Australia.
Nat Commun. 2012 Feb 21;3:687. doi: 10.1038/ncomms1693.
Rotary ATPases couple ATP hydrolysis/synthesis with proton translocation across biological membranes and so are central components of the biological energy conversion machinery. Their peripheral stalks are essential components that counteract torque generated by rotation of the central stalk during ATP synthesis or hydrolysis. Here we present a 2.25-Å resolution crystal structure of the peripheral stalk from Thermus thermophilus A-type ATPase/synthase. We identify bending and twisting motions inherent within the structure that accommodate and complement a radial wobbling of the ATPase headgroup as it progresses through its catalytic cycles, while still retaining azimuthal stiffness necessary to counteract rotation of the central stalk. The conformational freedom of the peripheral stalk is dictated by its unusual right-handed coiled-coil architecture, which is in principle conserved across all rotary ATPases. In context of the intact enzyme, the dynamics of the peripheral stalks provides a potential mechanism for cooperativity between distant parts of rotary ATPases.
旋转 ATP 酶将 ATP 水解/合成与质子跨生物膜转运偶联，是生物能量转换机制的核心组成部分。它们的外周柄部是对抗中央柄部在 ATP 合成或水解过程中旋转产生的扭矩的必要组成部分。在这里，我们展示了嗜热高温球菌 A 型 ATP 酶/合成酶外周柄部的 2.25 Å 分辨率晶体结构。我们确定了结构中固有的弯曲和扭曲运动，这些运动适应并补充了 ATP 酶头部在其催化循环中进行的径向摆动，同时仍然保留了抵抗中央柄部旋转所需的方位刚度。外周柄部的构象自由度由其独特的右手卷曲螺旋结构决定，该结构在原则上在所有旋转 ATP 酶中都得到了保守。在完整酶的背景下，外周柄部的动力学为旋转 ATP 酶中远距离部分之间的协同作用提供了一个潜在的机制。
