NMR studies of the antimicrobial salivary peptides histatin 3 and histatin 5 in aqueous and nonaqueous solutions
NMR studies of the antimicrobial salivary peptides histatin 3 and histatin 5 in aqueous and nonaqueous solutions
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DOI：
10.1139/bcb-76-2-3-247
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发表时间：
1998-01-01
期刊：
影响因子：
--
通讯作者：
Lajoie, G
中科院分区：
文献类型：
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作者：
Brewer, D;Hunter, H;Lajoie, G
用核磁共振和圆二色谱(CD)研究了唾液肽组蛋白3(H3)和组蛋白5(H5)在水溶液和非水溶液中的构象。组蛋白5在H2O中没有确定的结构，但在二甲基亚砜和三氟乙醇水溶液中采用了更螺旋的构象。这与CD分析是一致的，CD分析表明H2O中没有二级结构，但在三氟乙醇存在下螺旋含量增加。圆二色谱分析表明，在相同条件下，H3比H5更容易形成螺旋结构。对H3在pH为7.4的H2O中的核磁共振分析表明，H3的构象迁移率低于H5，观察到主链交叉峰αN(i，i+1)和NN(i，i+1)以及C-末端缓慢交换的酰胺质子。然而，H3基本上仍然是无序的，因为在NOESY谱中缺乏更远距离的核Overhauser效应(NOE)。H3在50：50H2O-二甲基亚砜的混合物中变得更加有序，如大量的NO所表明的，包括几个侧链到侧链和侧链到主链的连接性。我们的数据表明，在这些条件下，H3在K-13到K-17区域有一个转弯，在C-末端可能有一个3(10)螺旋。这项研究表明，H3和H5都是构象可移动的，并且在水和非水溶液中各自采用不同类型的构象。
Conformational studies of the salivary peptides histatin 3 (H3) and histatin 5 (H5) were performed by NMR and circular dichroism (CD) in aqueous and nonaqueous solutions. Histatin 5 has no defined structure in H2O but adopts a more helical conformation in dimethyl sulfoxide and aqueous trifluoroethanol. This is in agreement with the CD analysis, which shows no secondary structure in H2O but increasing helical content in the presence of trifluoroethanol. CD analysis shows that H3 has less propensity to form a helical structure than H5 in similar conditions. The NMR analysis of H3 in H2O at pH 7.4 reveals that its conformational mobility is less than that of H5 as indicated by the observation of backbone cross peaks alpha N (i, i + 1) and NN (i, i + 1) and the slow exchanging amide protons in the C-terminus. However, H3 remains essentially unordered as suggested by the lack of longer range nuclear Overhauser effects (NOEs) in the NOESY spectrum. H3 becomes much more ordered in a mixture of 50:50 H2O - dimethyl sulfoxide as indicated by the numerous NOEs, including several side chain to side chain and side chain to backbone conectivities. Our data suggest that in these conditions H3 contains a turn in the region of K-13 to K-17 and possibly a 3(10) helix at the C-terminus. This study demonstrates that H3 and H5 are both conformationally mobile and that each adopt different types of conformations in aqueous and nonaqueous solutions.