Monolayer formation and molecular orientation of various helical peptides at the air/water interface
Monolayer formation and molecular orientation of various helical peptides at the air/water interface
复制标题
各种螺旋肽在空气/水界面的单层形成和分子取向
作者：
K. Fujita;S. Kimura;Y. Imanishi;E. Okamura;J. Umemura
合成了10种螺旋多肽，用于研究在空气/水界面形成的多肽单层中螺旋之间的相互作用。其中5个具有Ala-AIB的重复序列和不同的端基，另外两个具有Lys(Z)-AIB的重复序列，其余的具有Leu-AIB的重复序列。经圆二色谱证实，所有多肽在乙醇中均呈螺旋构象。多肽单分子膜的表面压力-面积等温线在沿螺旋轴的横截面对应的表面积处出现拐点，此时单层膜被认为是坍塌的。将单分子膜转移到基片上，进行红外透射率和反射吸收光谱测试。通过比较酰胺I和酰胺II的吸光度，这些多肽似乎位于底物上。结果表明，单分子膜中的多肽螺旋轴平行于空气/水界面。
Ten kinds of helical peptides were synthesized to study interaction between helices in the peptide monolayer formed at the air/water interface. Five of those have a repeating sequence of Ala-Aib and different end groups, other two a repeating sequence of Lys(Z)-Aib, and the rest a repeating sequence of Leu-Aib. All of the peptides take helical conformation in ethanol as confirmed by CD spectroscopy. The surface pressure-area isotherms of the peptide monolayers showed an inflection at the surface area corresponding to the cross section along the helix axis, where the monolayers are considered to collapse. The monolayers were transferred onto substrates and subjected to IR transmission and reflection absorption spectroscopy. By comparison of amide I and II absorbances, the peptides seemed to lie on the substrates. It was concluded that the peptides in the monolayer orient their helical axis parallel to the air/water interface