Towards membrane protein design: PH-sensitive topology of histidine-containing polypeptides
Towards membrane protein design: PH-sensitive topology of histidine-containing polypeptides
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DOI：
10.1006/jmbi.1996.0614
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发表时间：
1996-11-15
影响因子：
5.6
通讯作者：
Bechinger, B
中科院分区：
文献类型：
--
作者：
Bechinger, B
疏水性和两亲性α -螺旋在免疫原性或融合原性多肽中作为独立的功能单元，并构成较大的膜蛋白的重要结构单元。为了定量评估决定膜相关α -螺旋排列的相互作用，通过固相肽合成制备了在选定位点含有组氨酸残基的疏水模型肽。CD和溶液核磁共振光谱表明，这些肽在胶束环境中具有α -螺旋二级结构。pH滴定实验中组氨酸侧链质子的化学位移变化表明，在十二烷基磷胆碱胶束存在下，组氨酸咪唑质子的pK值在4.9 ~ 6.6之间。N-15固态核磁共振波谱测定了这些肽-螺旋在单轴定向磷脂双分子层中的膜取向。观察到的其中一个模型肽的ph依赖性取向变化是由静电和疏水蛋白质-脂质相互作用控制的动态平衡定量描述的。所提出的热力学方程为预测膜蛋白的结构和拓扑结构以及未来多肽通道和药物的设计提供了一种手段。(C) 1996学术出版社有限公司
Hydrophobic and amphipathic alpha-helices act as independent functional units in immunogenic or fusogenic polypeptides and constitute important structural building blocks in larger membrane proteins. In order to quantitatively assess the interactions that determine the alignment of membrane-associated alpha-helices, hydrophobic model peptides containing histidine residues at selected sites were prepared by solid-phase peptide synthesis. CD and solution NMR spectroscopy show that these peptides assume alpha-helical secondary structures in micellar environments. The chemical shift alterations of the histidine side-chain protons during pH titration experiments indicate that the pK values of the histidine imidazole protons range from 4.9 to 6.6 in the presence of dodecylphosphocholine micelles. N-15 solid-state NMR spectroscopy was used to determine the membrane alignment of these peptide alpha-helices in uniaxially oriented phospholipid bilayers. The observed pH-dependent change of orientation of one of these model peptides is quantitatively described by a dynamic equilibrium governed by both electrostatic and hydrophobic protein-lipid interactions. The thermodynamic equations presented provide a means for the prediction of membrane protein structure and topology, as well as the future design of peptide channels and pharmaceuticals. (C) 1996 Academic Press Limited