The role of unstructured highly charged regions on the stability and specificity of dimerization of two-stranded α-helical coiled-coils:: Analysis of the neck-hinge region of the kinesin-like motor protein Kif3A
The role of unstructured highly charged regions on the stability and specificity of dimerization of two-stranded α-helical coiled-coils:: Analysis of the neck-hinge region of the kinesin-like motor protein Kif3A
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DOI：
10.1006/jsbi.2002.4446
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发表时间：
2002-01-01
影响因子：
3
通讯作者：
Hodges, RS
中科院分区：
文献类型：
--
作者：
Chana, M;Tripet, BP;Hodges, RS
我们研究了驱动蛋白样蛋白 Kif3A 的颈铰链区（残基 356-416）的折叠、稳定性和二聚化特异性。我们表明，预测的卷曲螺旋本身（残基 356-377）将在溶液中自主折叠。然后，我们通过合成颈部卷曲螺旋区域的类似物（带或不带各种带负电荷和正电荷的延伸至颈部卷曲螺旋的 C 末端）并通过圆二色光谱表征这些类似物，探索带相反电荷的区域在卷曲螺旋中形成异二聚体的能力。单独的带电区域（残基 378-416）采用随机螺旋结构，并且该区域在卷曲螺旋存在的情况下保持未折叠状态：氧化还原实验表明，带相反电荷的区域指定了异质双链卷曲螺旋的形成。尿素变性研究表明，在同链卷曲螺旋中添加带负电的残基会降低卷曲螺旋的稳定性；相反，将 Kif3A C 末端的带正电区域（残基 403-416）添加到颈部卷曲线圈不会影响卷曲线圈的稳定性。总体而言，我们的结果表明，静电吸引力驱动卷曲螺旋异二聚化的特异性，而不是消除正电荷或负电荷排斥，同时与最稳定的同二聚体相比，保持异二聚体的稳定性。 (C) 2002 年爱思唯尔科学（美国）。
We investigated the folding, stability, and specificity of dimerization of the neck-hinge region (residues 356-416) of the kinesin-like protein Kif3A. We showed that the predicted coiled-coil on its own (residues 356-377) will fold autonomously in solution. We then explored the ability of oppositely charged regions to specify heterodimer formation in coiled-coils by synthesizing analogs of the neck coiled-coil region with and without various negatively and positively charged extensions to the C-terminus of the neck coiled-coil and characterizing these analogs by circular dichroism spectroscopy. The charged region alone (residues 378-416) adopted a random-coil structure and this region remained unfolded in the presence of the coiled-coil: Redox experiments demonstrated that oppositely charged regions specified the formation of a hetero-two-stranded coiled-coil. Denaturation studies with urea demonstrated a decrease in coiled-coil stability with the addition of negatively charged residues in the homostranded coiled-coil; conversely, the addition of the positively charged region (residues 403-416) of Kif3A C-terminally to the neck coiled-coil did not affect coiled-coil stability. Overall, our results suggest that electrostatic attractions drive the specificity of heterodimerization of the coiled-coil, not the removal of positive or negative charge-charge repulsions, while maintaining the stability of the heterodimer compared to that of the stablest homodimer. (C) 2002 Elsevier Science (USA).