Preformed secondary structure drives the association reaction of GCN4-p1, a model coiled-coil system.
Preformed secondary structure drives the association reaction of GCN4-p1, a model coiled-coil system.
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DOI：
10.1006/jmbi.2000.3507
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发表时间：
2000-03
影响因子：
5.6
通讯作者：
J. Zitzewitz;Beatriz Ibarra-Molero;Deanna R Fishel;Kimberly L Terry;C. Matthews
中科院分区：
文献类型：
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作者：
J. Zitzewitz;Beatriz Ibarra-Molero;Deanna R Fishel;Kimberly L Terry;C. Matthews
通过突变分析，探讨了同源二聚体卷曲多肽GCN4-p1折叠结合限速步骤的过渡态结构。在七肽重复序列的四个外部f位置进行了一系列跨越螺旋倾向标尺的四重氨基酸替换。平衡和动力学圆二色谱研究表明，稳定性以及去折叠和复性速率常数都随螺旋倾向而变化，但也反映了改变的侧链与其局部环境的相互作用。成对置换和片段研究表明，两个C-端七头序列可能是成核螺旋的来源。在这种基本的折叠反应中，二级结构预制单元之间的螺旋-螺旋识别起着重要作用。
The structure of the transition state for the rate-limiting step in the folding and association of the homodimeric coiled-coil peptide GCN4-p1, was probed by mutational analysis. A series of quadruple amino acid replacements that spanned the helix propensity scale were made at the four external f positions in the heptad repeat. Equilibrium and kinetic circular dichroism studies demonstrate that both the stability and the unfolding and refolding rate constants vary with helix propensity but also reflect interactions of the altered side-chains with their local environments. Pairwise replacements and fragment studies show that the two C-terminal heptads are the likely source of the nucleating helices. Helix-helix recognition between preformed elements of secondary structure plays an important role in this fundamental folding reaction.