Self-association of glutamic acid-rich fusion peptide analogs of influenza hemagglutinin in the membrane-mimic environments: Effects of positional difference of glutamic acids on side chain ionization constant and intra- and inter-peptide interactions deduced from NMR and gel electrophoresis measurements
Self-association of glutamic acid-rich fusion peptide analogs of influenza hemagglutinin in the membrane-mimic environments: Effects of positional difference of glutamic acids on side chain ionization constant and intra- and inter-peptide interactions deduced from NMR and gel electrophoresis measurements
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DOI：
10.1016/j.bbamem.2005.04.003
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发表时间：
2005-06-15
影响因子：
3.4
通讯作者：
Wu, CW
中科院分区：
文献类型：
--
作者：
Chang, DK;Cheng, SF;Wu, CW
合成了两个富含谷氨酸的流感血凝素融合肽类似物，以研究带电肽在膜介质中的组织。荧光和凝胶电泳实验表明，在囊泡中的单体之间的松散关联。建立了一个模型，该模型表明位置差异3，7和4，8导致Glu 3和Glu 7侧链暴露于非极性的非极性核心。支持性结果包括：首先，对于Glu 3和Glu 7 C γ H，pK（a）值比水介质中的参考值高两个pH单位，而对于Glu 4和Glu 8 C γ H，pK（a）与参考值的偏差基本上较小;第二，这些质子的滴定位移的希尔系数表明Glu 3和Glu 7侧链质子的反协同性，但Glu 4和Glu 8的反协同性较低，这意味着Glu 3和Glu 7之间的强静电相互作用可能是由于它们在非极性环境中的定位造成的;第三，与Glu 4相比，观察到Glu 3的NH的正的和更大的滴定位移，表明NH与Glu 3的羧基之间的氢键比Glu 4的更强，这与Glu 3侧链更高程度地暴露于疏水介质相一致。(c)2005 Elsevier B. V.保留所有权利。
Two glutamic acid-rich fusion peptide analogs of influenza hemagglutinin were synthesized to study the organization of the charged peptides in the membranous media. Fluorescence and gel electrophoresis experiments suggested a loose association between the monomers in the vesicles. A model was built which showed that a positional difference of 3, 7 and 4, 8 results in the exposure of Glu3 and Glu7 side chains to the apolar lipidic core. Supportive results include: first, pK(a) values of two pH units higher than reference value in aqueous medium for Glu3 and Glu7 C gamma H, whereas the deviation of pK(a) from the reference value for Glu4 and Glu8 C gamma H is substantially smaller; second, Hill coefficients of titration shift of these protons indicate anti-cooperativity for Glu3 and Glu7 side chain protons but less so for Glu4 and Glu8, implying a strong electrostatic interaction between Glu3 and Glu7 possibly resulting from their localization in an apolar environment; third, positive and larger titration shift for NH of Glu3 is observed compared to that of Glu4, suggesting stronger hydrogen bond between the NH and the carboxylic group of Glu3 than that of Glu4, consistent with higher degree of exposure to hydrophobic medium for the side chain of Glu3. (c) 2005 Elsevier B.V. All rights reserved.