Vitagliano L, Berisio R, Mastrangelo A, Mazzarella L, Zagari A
Centro di Studio di Biocristallografia, CNR, I-80134 Napoli, Italy.
Protein Sci. 2001 Dec;10(12):2627-32. doi: 10.1110/ps.ps.26601a.
The interplay between side-chain and main-chain conformations is a distinctive characteristic of proline residues. Here we report the results of a statistical analysis of proline conformations using a large protein database. In particular, we found that proline residues with the preceding peptide bond in the cis state preferentially adopt a down puckering. Indeed, out of 178 cis proline residues, as many as 145 (81%) are down. By analyzing the 1-4 and 1-5 nonbonding distances between backbone atoms, we provide a structural explanation for the observed trend. The observed correlation between proline puckering and peptide bond conformation suggests a new mechanism to explain the reported shift of the cis-trans equilibrium in proline derivatives. The implications of these results for the current models of collagen stability are also discussed.
脯氨酸残基的侧链构象与主链构象之间的相互作用是其独特特征。在此,我们报告了使用大型蛋白质数据库对脯氨酸构象进行统计分析的结果。特别地,我们发现前一个肽键处于顺式状态的脯氨酸残基优先采取向下褶皱构象。实际上,在178个顺式脯氨酸残基中,多达145个(81%)是向下的。通过分析主链原子之间的1-4和1-5非键合距离,我们对观察到的趋势提供了结构解释。脯氨酸褶皱与肽键构象之间观察到的相关性提示了一种新机制,以解释脯氨酸衍生物中报道的顺反平衡的移动。还讨论了这些结果对当前胶原蛋白稳定性模型的影响。