Analysis of long-range interactions in a model denatured state of staphylococcal nuclease based on correlated changes in backbone dynamics.
Analysis of long-range interactions in a model denatured state of staphylococcal nuclease based on correlated changes in backbone dynamics.
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基于主链动力学相关变化分析葡萄球菌核酸酶模型变性状态下的长程相互作用。
DOI：
10.1110/ps.8.5.991
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Shortle,D
中科院分区：
文献类型：
--
作者：
Sinclair,JF;Shortle,D
葡萄球菌核酸酶的扩展的、高度动态变性状态在明显缺乏紧密堆积和固定氢键的情况下表现出天然样拓扑结构（吉莱斯皮JR，肖特尔D，1997，分子生物学杂志268：158-169，170-184）。为了解决这个分子的长程空间有序的物理基础，我们探测扰动的序列和溶液条件的影响，对本地链动力学的变性101个残基的片段，是失踪的前三个β链。链段之间的结构相互作用推断从相关的15 N NMR弛豫测量监测的残基的运动行为的变化。对应于前三条β链的序列的恢复显著增加了形成包括环的五条β链桶的所有链段的平均顺序，但对羧基末端30个残基没有影响。添加变性盐高氯酸钠增强了该片段整个序列的有序性。七个不同的取代突变体的分析点之间的相互作用的疏水性部分对应于β链5和链的其余部分的一组复杂的。数据中的一般模式表明，有一个层次的本地样的相互作用，发生在变性状态的瞬时和一致的整体拓扑结构的变性状态合奏确定许多耦合的本地相互作用，而不是一些高度特定的远程相互作用。
An expanded, highly dynamic denatured state of staphylococcal nuclease exhibits a native-like topology in the apparent absence of tight packing and fixed hydrogen bonds (Gillespie JR, Shortle D, 1997, J Mol Biol 268:158–169, 170–184). To address the physical basis of the long-range spatial ordering of this molecule, we probe the effects of perturbations of the sequence and solution conditions on the local chain dynamics of a denatured 101-residue fragment that is missing the first three beta strands. Structural interactions between chain segments are inferred from correlated changes in the motional behavior of residues monitored by 15N NMR relaxation measurements. Restoration of the sequence corresponding to the first three beta strands significantly increases the average order of all chain segments that form the five strand beta barrel including loops but has no effect on the carboxy terminal 30 residues. Addition of the denaturing salt sodium perchlorate enhances ordering over the entire sequence of this fragment. Analysis of seven different substitution mutants points to a complex set of interactions between the hydrophobic segment corresponding to beta strand 5 and the remainder of the chain. General patterns in the data suggest there is a hierarchy of native-like interactions that occur transiently in the denatured state and are consistent with the overall topology of the denatured state ensemble being determined by many coupled local interactions rather than a few highly specific long-range interactions.