Energised (entatic) states of groups and of secondary structures in proteins and metalloproteins.
Energised (entatic) states of groups and of secondary structures in proteins and metalloproteins.
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蛋白质和金属蛋白质中的基团和二级结构的赋能（实体）状态。
DOI：
10.1111/j.1432-1033.1995.363_b.x
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
R. J. Williams
中科院分区：
文献类型：
--
作者：
R. J. Williams
在这篇综述中，我考察了远离预期基态的蛋白质中孤立基团的选定状态的功能价值，无论它们是在蛋白质结构的较大部分有或没有能量扰动的情况下观察到的。在没有底物的情况下发现的这些能量被称为“基团的内在态”[Vallee，B.L.&Williams，R.J.P.(1968)Proc.纳特·阿卡德。SCI。美国59,498-505]。基团可以是氨基酸的一部分，也可以是任何结合的金属离子或辅因子。在某些特殊情况下，去掉带电的金属离子或辅因子，或替换带电的氨基酸的蛋白质，与全蛋白具有相同的骨架结构，甚至侧链也只有轻微的调整。这种情况与同时由蛋白质折叠提供能量的基团的情况非常不同，由于它们的结合，因此涉及蛋白质和基团的构象变化，并且可以在蛋白质收紧的同时调整基团。最后的条件又是稳定的，但现在去除基团必须导致蛋白质构象的反向变化。可调节蛋白质和基团的这种同时激励可以是局部的，如在诱导配合中，或者当它在某些情况下可以比作通过齿条动作的伸展时更广泛，或者当基团以非常有限的方式被激励时，可以涉及从几乎随机的蛋白质到结构蛋白的改变。不同的能量不能混淆，因为它们在功能上是不同的。前者可以产生局部基团的最佳增强催化(或其他功能)势，但既不能像诱导拟合那样与蛋白质其他部分的激发有关，也不能与蛋白质中的能量继电器(更大的构象变化)联系起来。显然，它限制了一组人的汇率。诱导性匹配也可以引起群体激活，尽管程度有所降低，但同时增加了汇率。像支架这样的设备可能会引起机械活动(信息传输)，这种活动被传递到蛋白质中很远的距离，并且只能对单个群体产生相当低的激活，但现在交换可能很快。最后一种情况涉及蛋白质粗大重排和带电的非常轻微的基团带电，可能与储存或载体功能有关。我关注的基团是金属离子，因为它们的基态的详细电子和结构知识是众所周知的，因此很容易检测到带电状态，但这些想法同样适用于蛋白质的有机侧链，如下所示。在每种蛋白质中添加一种底物可以产生进一步的能量。事实上，所有适用于在蛋白质结构的永久特征中具有循环活性的基团的能化思想同样适用于底物结合或通过激发态将底物转化为产物。
In this review I have examined the functional value of selected states of isolated groups in proteins energised away from their expected ground states whether they are observed with or without energy perturbation of larger parts of a protein structure. These energisations, found in the absence of substrates, are called 'entatic states of groups' [Vallee, B. L. & Williams, R. J. P. (1968) Proc. Natl Acad. Sci. USA 59, 498-505]. A group can be part of an amino acid or any bound metal ion or cofactor. In some particular cases the apoprotein, where the energised metal ion or cofactor has been removed, or the protein in which the energised amino acid has been replaced, has the same back-bone structure as the holoprotein and even side-chains are only slightly adjusted. This case is quite different from a condition of a group simultaneously energised with a protein fold, due to their combination, and which therefore involves conformational change in the protein and the group and which may adjust the group while the protein tightens. The final condition is again stable but removal of the group now must result in a reversed protein conformation change. This simultaneous energisation of both the adjustable protein and the group can be local, as in an induced fit or more extensive when it can be likened in some cases to a stretching by rack action, or may involve a change from an almost random to a structured protein when the group is energised in a very limited way. The various energisations must not be confused since they differ functionally. The first can give rise to optimal heightened catalytic (or other functional) potential of the local group but cannot be connected either to excitation of other parts of a protein as in induced fitting, or to a relay of energy (larger conformational change) in the protein. Clearly it restricts the rate of exchange of a group. Induced fit can also give rise to group activation, though to a somewhat reduced degree, while increasing exchange rate. A device such as a rack may rather give rise to a mechanical activity (message transmission), which is relayed a large distance into the protein, and can only give considerably lower activation of individual groups but exchange may now be fast. The final case involves very modest energisation of the group with gross rearrangement and energisation of the protein and may be associated with storage or carrier functions. The groups upon which I concentrate are metal ions since detailed electronic and structural knowledge of their ground states are well known, allowing energised states to be easily detected, but the ideas apply equally to organic side-chains of proteins as will be shown. A further energisation can arise from the addition of a substrate to each kind of protein. In fact all the ideas of energisation applicable to groups having cyclic activity in permanent features of protein structure are equally well applied to substrate binding or conversion of substrates through excited states to products.
影响因子：
5.6
作者：
TAINER, JA;GETZOFF, ED;RICHARDSON, DC
通讯作者：
RICHARDSON, DC
作为细胞色素 c 早期折叠中间体模型的非共价肽复合物。
影响因子：
2.9
作者：
Wu,LC;Laub,PB;Elöve,GA;Carey,J;Roder,H
通讯作者：
Roder,H
影响因子：
56.9
作者：
SOLOMON, EI;LOWERY, MD
通讯作者：
LOWERY, MD