Transition state heterogeneity in GCN4 coiled coil folding studied by using multisite mutations and crosslinking.
Transition state heterogeneity in GCN4 coiled coil folding studied by using multisite mutations and crosslinking.
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DOI：
10.1073/pnas.96.19.10699
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发表时间：
1999-09
影响因子：
11.1
通讯作者：
Liam B. Moran;Joel P. Schneider;A. Kentsis;Giridher A. Reddy;T. Sosnick
中科院分区：
文献类型：
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作者：
Liam B. Moran;Joel P. Schneider;A. Kentsis;Giridher A. Reddy;T. Sosnick
我们研究了来自转录激活剂GCN4的亮氨酸拉链区域的33个残基α-螺旋GCN4-p1卷曲的二聚体和共价交联形式的折叠行为。多位点替换的影响表明，折叠沿着多条路线发生，成核位置位于整个蛋白质中。不同路线的活化能的相似性以及对固有螺旋倾向的分析表明，在两条链发生生产性碰撞之前，存在最小的螺旋。然而，大约三分之一到一半的总螺旋结构是在碰撞后过渡态系综中形成的。对于交联的单体版本，折叠沿着单一的强健路径发生。在这里，最接近交联键的区域具有最小的螺旋倾向，处于过渡态，而距离系链最远的区域具有最大的倾向，完全是无结构的。因此，过渡态异质性的存在和折叠路径的选择很大程度上取决于链拓扑结构。
We have investigated the folding behavior of dimeric and covalently crosslinked versions of the 33-residue alpha-helical GCN4-p1 coiled coil derived from the leucine zipper region of the transcriptional activator GCN4. The effects of multisite substitutions indicate that folding occurs along multiple routes with nucleation sites located throughout the protein. The similarity in activation energies of the different routes together with an analysis of intrinsic helical propensities indicate that minimal helix is present before a productive collision of the two chains. However, approximately one-third to one-half of the total helical structure is formed in the postcollision transition state ensemble. For the crosslinked, monomeric version, folding occurs along a single robust pathway. Here, the region nearest the crosslink, with the least helical propensity, is structured in the transition state whereas the region farthest from the tether, with the most propensity, is completely unstructured. Hence, the existence of transition state heterogeneity and the selection of folding routes critically depend on chain topology.