Cavities and Excited States in Proteins.
Cavities and Excited States in Proteins.
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蛋白质中的空腔和激发态。
DOI：
10.1007/978-94-017-9918-8_12
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Kamatari YO.
中科院分区：
文献类型：
--
作者：
Li H;Kamatari YO.
观察到蛋白质空腔或空隙作为原子堆积中的缺陷。长期以来，人们一直认为空腔在蛋白质动力学和功能中发挥重要作用，但其潜在的起源和机制仍然难以捉摸。本文综述了近年来高压核磁共振谱表征空穴的研究进展。压力依赖性的化学位移的分析表明，线性和非线性的蛋白质的压力响应。线性响应对应于本机合奏内的压缩，而非线性响应表明参与的低躺激发态，是从本机状态不同。在各种蛋白质中发现的非线性压力变化表明，低激发态的存在是常见的球状蛋白质。然而，绝对非线性系数值变化显着蛋白质，并表现出良好的相关性与空洞的密度。以鸡溶菌酶为模型体系的研究表明，空腔水合和水渗透到蛋白质内部是蛋白质构象向激发态转变的起源。空腔对蛋白质功能和进化的重要性也得到了解释。除了这些“平衡”空腔，也有“瞬态”空腔形成的内部的蛋白质结构，表现为环翻转运动的芳香环。瞬态腔的意义，反映了本机状态内的内在动力学性质，也进行了讨论。
Protein cavities or voids are observed as defects in atomic packing. Cavities have long been suggested to play important roles in protein dynamics and function, but the underlying origin and mechanism remains elusive. Here, recent studies about the cavities characterized by high-pressure NMR spectroscopy have been reviewed. Analysis of the pressure-dependent chemical shifts showed both linear and nonlinear response of proteins to pressure. The linear response corresponded to compression within the native ensemble, while the nonlinear response indicated the involvement of low-lying excited states that were different from the native state. The finding of non-linear pressure shifts in various proteins suggested that the existence of the low-lying excited states was common for globular proteins. However, the absolute nonlinear coefficient values varied significantly from protein to protein, and showed a good correlation with the density of cavities. Extensive studies on hen lysozyme as a model system showed that the cavity hydration and water penetration into the interior of proteins was an origin of the conformational transition to the excited states. The importance of cavities for protein function and evolution has also been explained. In addition to these “equilibrium” cavities, there are also “transient” cavities formed in the interior of the protein structure, as manifested by the ring flip motions of aromatic rings. The significance of transient cavities, reflecting an intrinsic dynamic nature within the native state, has also been discussed.