| Abstract
| - Conformational changes of α-mycolic acid (α-MAMAI, isolated from Mycobacterium avium−M. intracellularecomplex) 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 tothe gas, liquid-expanded, and solid states were prepared and transferred onto freshly cleaved mica. Themonolayer 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 picturesfor 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. Theresults suggested that the α-MAMAI molecules partially took a flat-on stance in the gas-state monolayerand that the full extension of the longer alkyl chain of the molecule in the monolayer was possible onlywhen the monolayer was highly compressed to the solid state.
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