Conformational Characterization of α-Mycolic Acid in a Monolayer Film by the Langmuir−Blodgett Technique and Atomic Force Microscopy
Conformational Characterization of α-Mycolic Acid in a Monolayer Film by the Langmuir−Blodgett Technique and Atomic Force Microscopy
复制标题
通过 Langmuir-Blodgett 技术和原子力显微镜对单层膜中 α-霉菌酸的构象表征
作者：
T. Hasegawa;and Jujiro Nishijo;Motoko Watanabe;Katsuya Funayama§ and;T. Imae
鸟分枝杆菌α-霉菌酸（α-MAMAI）的构象变化利用Langmuir - Blodgett （LB）技术和原子力显微镜（AFM）研究了不同表面压力下其单层细胞内复合体的结构。制备了三个具有代表性的单分子层，分别对应于气体、液体膨胀和固体状态，并将其转移到新切割的云母上。采用原子力显微镜（AFM）对α-MAMAI单层LB膜在厚度方向上进行了埃分辨研究。通过对单层形貌和横截面的观察，给出了α-MAMAI在不同表面压力下在单层中烷基链横向排列的一系列示意图。所提出的分子构象与表面压力-面积等温线一致。结果表明，α-MAMAI分子在气态单分子层中部分呈平on状态，而在单分子层中较长的烷基链完全延伸。
Conformational changes of α-mycolic acid (α-MAMAI, isolated from Mycobacterium avium−M. intracellulare complex) in its monolayer at different surface pressures were investigated by using the Langmuir−Blodgett (LB) technique and atomic force microscopy (AFM). Three representative monolayers that correspond to the gas, liquid-expanded, and solid states were prepared and transferred onto freshly cleaved mica. The monolayer LB films of α-MAMAI were examined by AFM in an angstrom resolution in the thickness direction. The observation of topography and cross section of the monolayers proposed a series of schematic pictures for the lateral arrangement of the alkyl chains of α-MAMAI in the monolayer at different surface pressures. The proposed molecular conformations were consistent with the surface pressure−area isotherm. The results suggested that the α-MAMAI molecules partially took a flat-on stance in the gas-state monolayer and that the full extension of the longer alkyl chain of the molecule in the monolaye...