Circular dichroism of polypeptide monolayers
Circular dichroism of polypeptide monolayers
复制标题
多肽单层的圆二色性
DOI：
10.1016/0021-9797(79)90021-3
复制
发表时间：
1979
期刊：
影响因子：
2.9
通讯作者：
D. Cornell
中科院分区：
文献类型：
--
作者：
D. Cornell
测定了从朗缪尔膜天平的气-水界面收集的聚-γ-L-谷氨酸甲酯和聚L-丙氨酸的单分子膜和塌陷膜的圆二色谱。多肽膜是通过在各种溶剂中铺展形成的，然后转移到石英板上进行CD分光光度测定。当所有平板在光谱旋光仪的光束中相同排列时，PMG和PA的薄膜表现出线性二色性，可用于确定聚合物链在薄膜天平表面的取向。在围绕入射光束轴线成多个角度取向的薄膜上，获得了不含线性成分的真实CD光谱。α-螺旋构象的PA和PMG薄膜的CD光谱与螺旋轴垂直于光传播方向的多肽的预期光学性质一致。PMG膜具有α-螺旋或β-构象的光谱特征，这取决于形成单分子膜所用的铺展溶剂。PMG和PA薄膜的压强-面积和表面电位曲线，以及对CD光谱的解释，都与以前的红外光谱研究结果一致。给出了用于圆二色谱的多肽单分子膜的制备和安装的细节。
The circular dichroism (CD) spectra of Langmuir—Blodgett monolayers and collapsed films of poly-γ-methyl-l-glutamate (PMG) and poly-l-alanine (PA) collected from the air-water interface of a Langmuir film balance have been determined. The polypeptide films were formed by spreading from a variety of solvents, followed by transfer to quartz plates for CD spectrophotometry. When all plates were aligned identically in the light beam of the spectropolarimeter, films of PMG and PA exhibited linear dichroism which could be used to determine the orientation of the polymer chains on the surface of the film balance. True CD spectra, free of linear component, were obtained on films oriented at numerous angles around the axis of the incident light beam. The CD spectra of films of PA and PMG in the α-helical conformation were consistent with the optical properties expected of polypeptides which have the helix axis perpendicular to the direction of propagation of light. PMG films gave spectra characteristic of the α-helix or β-conformation, depending on the spreading solvent used to form the monolayers. The pressure-area and surface potential curves, as well as the interpretation of the CD spectra of PMG and PA films, were all consistent with the results of previous investigations employing infrared spectroscopy. Details of preparing and mounting polypeptide monolayers for CD spectroscopy are given.