Vishnepol'skiĭ B M, Pirtskhalava M K
Mol Biol (Mosk). 1993 May-Jun;27(3):631-7.
Distribution of nonpolar residues in the hydrophobic core (a and d positions) of fibrillar proteins in the form of alpha-helical coiled-coil has been studied. It was shown that concentration of large nonpolar residues (Phe, Trp) in a and d positions would not stabilize this structure; amino acids with smaller nonpolar side chains (Leu, Ala, Val, Ile, Met) are preferable, and Leu is the most preferred amino acid in the hydrophobic core; nonpolar residues with branching at the C beta atom (Val, Ile) prefer the a to the d position. The results obtained show that the distribution of nonpolar residues in the a and d positions of the alpha-helical coiled-coil cannot be only accounted for hydrophobic interactions between nonpolar residues of adjacent helices in the considered structure.
对呈α-螺旋卷曲螺旋形式的纤维状蛋白质疏水核心（a和d位）中非极性残基的分布进行了研究。结果表明，a和d位中大的非极性残基（苯丙氨酸、色氨酸）的浓度不会稳定这种结构；具有较小非极性侧链的氨基酸（亮氨酸、丙氨酸、缬氨酸、异亮氨酸、甲硫氨酸）更合适，亮氨酸是疏水核心中最优选的氨基酸；在Cβ原子处有分支的非极性残基（缬氨酸、异亮氨酸）优先占据a位而非d位。所得结果表明，α-螺旋卷曲螺旋a和d位中非极性残基的分布不能仅用所考虑结构中相邻螺旋的非极性残基之间的疏水相互作用来解释。
