Crystal structures of collagen model peptides with Pro-Hyp-Gly repeating sequence at 1.26 Å resolution:: Implications for proline ring puckering
Crystal structures of collagen model peptides with Pro-Hyp-Gly repeating sequence at 1.26 Å resolution:: Implications for proline ring puckering
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DOI：
10.1002/bip.20107
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发表时间：
2004-01-01
期刊：
影响因子：
2.9
通讯作者：
Nishino, N
中科院分区：
文献类型：
--
作者：
Okuyama, K;Hongo, C;Nishino, N
利用同步辐射数据分析了（Pro-Hyp-Gly）n（n = 10，11）在100 K和室温下的三螺旋结构，分辨率为1.26埃。在100 K和RT下，分别发现每七个不对称单元中的三重态共有49和42个水分子。这些水分子被分为两组，即第一和第二水化壳层中的水分子。虽然在100 K时第一壳层中的水分子与室温下的水分子之间没有显著差异，但观察到第二壳层中的水分子之间存在显著差异。也就是说，在RT下水分子的数量减少到一半，并且在RT下与肽链的平均距离变长约0.3埃。另一方面，在一个不对称单元的七个三重峰中，在100 K时X位置的三个脯氨酸残基清楚地显示出向上起皱的构象，而不是最近的倾向为基础的假设，通过脯氨酸羟基化的三螺旋结构的稳定和不稳定。这种褶皱是由于脯氨酸环和周围的水分子之间的相互作用，在100 K，这是弱得多，在RT下，所示的平均距离较长的肽链。(C)2004 Wiley Periodicals，Inc.
Triple-helical structures of (Pro-Hyp-Gly)n (n = 10, 11) at 100 K and room temperature (RT) were analyzed at 1.26 Angstrom resolution by using synchrotron radiation data. Totals of 49 and 42 water molecules per seven triplets in an asymmetric unit were found for the structures at 100 K and RT, respectively. These water molecules were classified into two groups, those in the first and second hydration shells. Although there was no significant difference between water molecules in the first shell at 100 K and those at RT, a significant difference between those in the second shell was observed. That is, the number of water molecules at RT decreased to one half and the average distance from peptide chains at RT became longer by about 0.3 Angstrom. On the other hand, of seven triplets in an asymmetric unit, three praline residues at the X position at 100 K clearly showed an up-puckering conformation, as opposed to the recent propensity-based hypothesis for the stabilization and destabilization of triple-helical structures by proline hydroxylation. This puckering was attributed to the interaction between proline rings and the surrounding water molecules at 100 K, which is much weaker at RT, as shown by longer average distance from peptide chains. (C) 2004 Wiley Periodicals, Inc.