Crystal structure of GCN4-pIQI, a trimeric coiled coil with buried polar residues
Crystal structure of GCN4-pIQI, a trimeric coiled coil with buried polar residues
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DOI：
10.1006/jmbi.1998.2214
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发表时间：
1998-12-11
影响因子：
5.6
通讯作者：
Kim, PS
中科院分区：
文献类型：
--
作者：
Eckert, DM;Malashkevich, VN;Kim, PS
卷曲螺旋由两个或更多个α-螺旋组成，它们以超螺旋扭曲相互缠绕。卷曲螺旋的螺旋之间的界面由以“钮入孔”排列的疏水氨基酸残基形成。然而，大多数天然存在的卷曲螺旋也含有埋藏的极性残基，就像大多数天然存在的球状蛋白质的核心一样。二聚体和三聚体卷曲螺旋中两个常见的埋藏极性残基是天冬酰胺和谷氨酰胺。在二聚体卷曲螺旋中，掩埋的天冬酰胺残基而不是谷氨酰胺残基已被证明赋予寡聚化的特异性。我们已经放置了谷氨酰胺残基，否则疏水内部的稳定的三聚体卷曲螺旋，GCN 4-pII，研究这种埋极性残基在三聚体卷曲螺旋环境的影响。所得肽GCN 4- pI（Q）I是一种离散的三聚体卷曲螺旋，其稳定性低于GCN 4-pII。在1.8埃下测定的晶体结构表明，GCN 4-pI（Q）I是一种三聚体卷曲螺旋，其中氯离子与来自每个单体的一个埋藏的谷氨酰胺残基配位。(C)北京：科学出版社.
Coiled coils consist of two or more alpha-helices wrapped around each other with a superhelical twist. The interfaces between helices of a coiled coil are formed by hydrophobic amino acid residues packed in a "knobs-into-holes" arrangement. Most naturally occurring coiled coils, however, also contain buried polar residues, as do the cores of the majority of naturally occurring globular proteins. Two common buried polar residues in both dimeric and trimeric coiled coils are asparagine and glutamine. In dimeric coiled coils, buried asparagine, but not glutamine, residues have been shown to confer specificity of oligomerization. We have placed a glutamine residue in the otherwise hydrophobic interior of a stable trimeric coiled coil, GCN4-pII, to study the effect of this buried polar residue in a trimeric coiled-coil environment. The resulting peptide, GCN4- pI(Q)I, is a discrete, trimeric coiled coil with a lower stability than GCN4-pII. The crystal structure determined to 1.8 Angstrom shows that GCN4-pI(Q)I is a trimeric coiled coil with a chloride ion coordinated by one buried glutamine residue from each monomer. (C) 1998 Academic Press.