Construction of Langmuir–Blodgett films from light-harvesting complex I isolated from photosynthetic bacteria

Langmuir–Blodgett (LB) films of the light-harvesting (LH) polypeptides/bacteriochlorophyll a (BChl a) complex isolated from photosynthetic bacteria, Rhodospirillum rubrum, were constructed. The monolayers of the core LH /BChl a complex were prepared from octyl β-glycoside suspensions at an air/water interface and then the monolayer was transferred to glass slides using LB technique multilayer films. UV-vis absorption spectra of the LB layer films absorbing 870 nm at the Qy absorption of BChl a indicated that the LH/BChl a complex in the multilayer films was more stable than the subunit complex absorbing 820 nm at the Qy absorption. Analysis of Fourier transform infrared reflection absorption spectroscopy (FTIR-RAS) spectra showed that the tilt angle of the transmembrane axis of the LH/BChl a complex in the multilayer films was 40° to the normal.