Efimov A V
Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, Russia.
Biochemistry (Mosc). 2007 Feb;72(2):188-91. doi: 10.1134/s0006297907020083.
In this study, a possible mechanism of selection of side-chain rotamers based on the rotamer distributions in known coiled-coil proteins is suggested. According to this mechanism, interhelical hydrophobic, polar, and packing interactions bring alpha-helices closer to each other and this effect squeezes side chains out of the helix-helix interface. As a result, in dimeric coiled coils and long alpha-alpha-hairpins where alpha-helices are packed in a face-to-face manner, most side chains occupying the a-positions have t-rotamers and those in the d-positions g(-)-rotamers. In tetramers, where alpha-helices are packed side-by-side, most side chains in the a-positions adopt g(-)-rotamers and those in the d-positions t-rotamers.
在本研究中，基于已知卷曲螺旋蛋白中旋转异构体的分布，提出了一种侧链旋转异构体选择的可能机制。根据该机制，螺旋间的疏水、极性和堆积相互作用使α螺旋彼此靠近，这种效应将侧链挤出螺旋-螺旋界面。结果，在二聚体卷曲螺旋和α-α-发夹结构中，α螺旋以面对面的方式堆积，占据a位的大多数侧链具有t旋转异构体，而占据d位的侧链具有g(-)旋转异构体。在四聚体中，α螺旋并排堆积，a位的大多数侧链采用g(-)旋转异构体，d位的侧链采用t旋转异构体。
