Department of Chemistry, University of Michigan , Ann Arbor, Michigan 48109, United States.
Langmuir. 2013 Sep 17;29(37):11705-12. doi: 10.1021/la401818k. Epub 2013 Sep 3.
Sum frequency generation (SFG) vibrational spectroscopy and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) were used to investigate the orientation of N-terminus cysteine-modified cecropin P1 (cCP1) at the polystyrene maleimide (PS-MA)/peptide phosphate buffer solution interface. The cCP1 cysteine group reacts with the maleimide group on the PS-MA surface to chemically immobilize cCP1. Previously, we found that the C-terminus cysteine-modified cecropin P1 (CP1c) molecules exhibit a multiple-orientation distribution at the PS-MA/peptide phosphate buffer solution interface, due to simultaneous physical adsorption and chemical immobilization of CP1c on the PS-MA surface. Differently, in this research, it was found that the interfacial orientation of cCP1 molecules varied from a horizontal orientation to the "tilting" orientation to the "standing up" orientation and then to the "multiple-orientation" distribution as the peptide concentration increased from 0.19 to 3.74 μM. This research shows the different interaction mechanisms between CP1c and PS-MA and between cCP1 and PS-MA.
利用和频发生（SFG）振动光谱和衰减全反射傅里叶变换红外光谱（ATR-FTIR）研究了 N 端半胱氨酸修饰的抗菌肽 Cecropin P1（cCP1）在聚苯乙烯马来酰亚胺（PS-MA）/肽磷酸盐缓冲溶液界面的取向。cCP1 的半胱氨酸基团与 PS-MA 表面上的马来酰亚胺基团反应，将 cCP1 化学固定。先前，我们发现 C 端半胱氨酸修饰的抗菌肽 Cecropin P1（CP1c）分子在 PS-MA/肽磷酸盐缓冲溶液界面上呈现出多重取向分布，这是由于 CP1c 同时通过物理吸附和化学固定在 PS-MA 表面上。与此不同，在这项研究中，发现随着肽浓度从 0.19 μM 增加到 3.74 μM，cCP1 分子的界面取向从水平取向变为“倾斜”取向，再变为“站立”取向，然后变为“多重”取向分布。这项研究表明 CP1c 和 PS-MA 之间以及 cCP1 和 PS-MA 之间的相互作用机制不同。
