A Euclidean perspective on the unfolding of azurin: chain motion.
A Euclidean perspective on the unfolding of azurin: chain motion.
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关于天青蛋白展开的欧几里得观点：链运动。
DOI：
10.1007/s00775-013-1077-2
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Kozak,JohnJ
中科院分区：
文献类型：
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作者：
Gray,HarryB;Warren,JefferyJ;Winkler,JayR;Kozak,JohnJ
我们提出了一种新的方法来可视化和量化的位移段ofPseudomonasaerosaazurin在早期阶段的变性。我们的方法是基于作者以前开发的几何方法，并详细阐述了天青蛋白。在这项研究中，我们量化了三个α-螺旋区域，两个区域的β-链残基，和三个非结构化区域的天青蛋白的方向变化。这些变化的快照，蛋白质展开显示和定量描述引入一个缩放诊断。与分子动力学模拟雅阁，我们发现天青蛋白中的长α-螺旋（残基54-67）从多肽支架上移位，然后首先向一个方向枢转，然后随着蛋白质继续展开而向相反方向枢转。这两条β链基本上保持完整，除了在最早的阶段，它们是串联运动的。我们发现，非结构化区域72-81和84-91，由β链残基82-83铰接，反向枢转。包含残基72-91（40%疏水性和128个总残基的16%）的区域形成有效的固定区域，其随着蛋白质展开而持续存在。这种静态行为是残基72-81和残基84-91这两个片段的竞争运动之间的动态平衡的结果。
We present a new approach to visualizing and quantifying the displacement of segments ofPseudomonas aeruginosaazurin in the early stages of denaturation. Our method is based on a geometrical method developed previously by the authors, and elaborated extensively for azurin. In this study, we quantify directional changes in three α-helical regions, two regions having β-strand residues, and three unstructured regions of azurin. Snapshots of these changes as the protein unfolds are displayed and described quantitatively by introducing a scaling diagnostic. In accord with molecular dynamics simulations, we show that the long α-helix in azurin (residues 54–67) is displaced from the polypeptide scaffolding and then pivots first in one direction, and then in the opposite direction as the protein continues to unfold. The two β-strand chains remain essentially intact and, except in the earliest stages, move in tandem. We show that unstructured regions 72–81 and 84–91, hinged by β-strand residues 82–83, pivot oppositely. The region comprising residues 72–91 (40 % hydrophobic and 16 % of the 128 total residues) forms an effectively stationary region that persists as the protein unfolds. This static behavior is a consequence of a dynamic balance between the competing motion of two segments, residues 72–81 and 84–91.