Tsai Chung-Jung, del Sol Antonio, Nussinov Ruth
Basic Research Program, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program, NCI-Frederick, Frederick, MD 21702, USA.
J Mol Biol. 2008 Apr 18;378(1):1-11. doi: 10.1016/j.jmb.2008.02.034. Epub 2008 Feb 29.
Allostery is essential for controlled catalysis, signal transmission, receptor trafficking, turning genes on and off, and apoptosis. It governs the organism's response to environmental and metabolic cues, dictating transient partner interactions in the cellular network. Textbooks taught us that allostery is a change of shape at one site on the protein surface brought about by ligand binding to another. For several years, it has been broadly accepted that the change of shape is not induced; rather, it is observed simply because a larger protein population presents it. Current data indicate that while side chains can reorient and rewire, allostery may not even involve a change of (backbone) shape. Assuming that the enthalpy change does not reverse the free-energy change due to the change in entropy, entropy is mainly responsible for binding.
别构作用对于可控催化、信号传导、受体运输、基因的开启与关闭以及细胞凋亡至关重要。它控制着生物体对环境和代谢信号的反应，决定了细胞网络中瞬时伙伴间的相互作用。教科书告诉我们，别构作用是蛋白质表面一个位点因配体与另一位点结合而发生的形状变化。多年来，人们普遍认为这种形状变化并非被诱导产生；相反，仅仅是因为更大比例的蛋白质群体呈现出这种变化才被观察到。目前的数据表明，虽然侧链可以重新定向和重新连接，但别构作用甚至可能不涉及（主链）形状的变化。假设焓变不会因熵变而逆转自由能变化，那么熵主要负责结合。
