Shi Z, Olson C A, Bell A J, Kallenbach N R
Department of Chemistry, New York University, NY 10003, USA.
Biopolymers. 2001;60(5):366-80. doi: 10.1002/1097-0282(2001)60:5<366::AID-BIP10177>3.0.CO;2-5.
It is generally understood that helical proteins are stabilized by a combination of hydrophobic and packing interactions, together with H-bonds and electrostatic interactions. Here we show that polar side-chain interactions on the surface can play an important role in helix formation and stability. We review studies on model helical peptides that reveal the effect of weak interactions between side chains on helix stability, focusing on some nonclassical side-chain-side-chain interactions: complex salt bridges, cation-pi, and C-H em leader O H-bonding interactions. Each of these can be shown to contribute to helix stability, and thus must be included in a comprehensive catalogue of helix stabilizing effects. The issue of the structure of the unfolded states of helical peptides is also discussed, in the light of recent experiments showing that these contain substantial amounts of polyproline II conformation.
人们普遍认为，螺旋蛋白是通过疏水作用、堆积相互作用以及氢键和静电相互作用的共同作用而稳定的。在此我们表明，表面上的极性侧链相互作用在螺旋形成和稳定性方面可发挥重要作用。我们回顾了对模型螺旋肽的研究，这些研究揭示了侧链间弱相互作用对螺旋稳定性的影响，重点关注一些非经典的侧链 - 侧链相互作用：复合盐桥、阳离子 - π相互作用以及C - H···O氢键相互作用。这些相互作用中的每一种都可被证明有助于螺旋稳定性，因此必须纳入螺旋稳定效应的综合目录中。鉴于最近的实验表明螺旋肽的未折叠状态包含大量的多聚脯氨酸II构象，我们还讨论了螺旋肽未折叠状态的结构问题。
