Water Scaffolding in Collagen: Implications on Protein Dynamics as Revealed by Solid-State NMR
Water Scaffolding in Collagen: Implications on Protein Dynamics as Revealed by Solid-State NMR
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DOI：
10.1002/bip.22330
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发表时间：
2014-03-01
期刊：
影响因子：
2.9
通讯作者：
Courtier-Murias, Denis
中科院分区：
文献类型：
--
作者：
Aliev, Abil E.;Courtier-Murias, Denis
对不同来源的胶原蛋白样品的固态核磁共振研究证实，随着水含量的增加，胶原蛋白主链和侧链运动的幅度显着增加。这一结论得到了三个不同 NMR 可观测值中观察到的变化的支持：(i) 线宽对 H-1 去耦频率的依赖性； (ii) 肽羰基的 C-13 CSA 变化，以及 (iii) H-1-C-13 偶极耦合的相移速率。特别是，当添加的水含量增加至 47 wt% D2O 时，发现关于 C-C 或 N-C 键的主链振动的运动幅度增加了近三倍。根据所涉及的核磁共振观测值的频率，依赖于添加的水含量的蛋白质运动的时间尺度估计为微秒量级。该估计与宽线 T-2 H-1 NMR 测量的结果一致。此外，我们的宽线 H-1 NMR 测量表明，随着添加水含量的增加，蛋白质中微秒运动的时间尺度显着减少，即，当添加水含量增加到 45 wt% D2O 时，观察到蛋白质运动频率增加了约 15 倍。观察到的胶原动力学变化归因于添加水量增加时水平移扩散的增加，这导致蛋白质表面上更频繁的结合水/自由水交换，伴随着蛋白质极性功能的新氢键的断裂和形成。 (c) 2013 年 Wiley 期刊公司。生物聚合物 101：246-256，2014 年。
Solid-state NMR studies of collagen samples of various origins confirm that the amplitude of collagen backbone and sidechain motions increases significantly on increasing the water content. This conclusion is supported by the changes observed in three different NMR observables: (i) the linewidth dependence on the H-1 decoupling frequency; (ii) C-13 CSA changes for the peptide carbonyl groups, and (iii) dephasing rates of H-1-C-13 dipolar couplings. In particular, a nearly threefold increase in motional amplitudes of the backbone librations about C-C or N-C bonds was found on increasing the added water content up to 47 wt%D2O. On the basis of the frequencies of NMR observables involved, the timescale of the protein motions dependent on the added water content is estimated to be of the order of microseconds. This estimate agrees with that from wideline T-2 H-1 NMR measurements. Also, our wideline H-1 NMR measurements revealed that the timescale of the microsecond motions in proteins reduces significantly on increasing the added water content, i.e., an approximate to 15-fold increase in protein motional frequencies is observed on increasing the added water content to 45 wt% D2O. The observed changes in collagen dynamics is attributed to the increase in water translational diffusion on increasing the amount of added water, which leads to more frequent bound water/free water exchange on the protein surface, accompanied by the breakage and formation of new hydrogen bonds with polar functionalities of protein. (c) 2013 Wiley Periodicals, Inc. Biopolymers 101: 246-256, 2014.