Jn. He et al., LANGMUIR-BLODGETT-FILMS OF PHYCOBILIPROTEINS .1. MONOMOLECULAR FILM AND CONFORMATIONAL STUDIES OF R-PHYCOERYTHRIN, Science in China. Series B, Chemistry, life sciences & earth sciences, 39(3), 1996, pp. 327-336
The surface pressure-area (pi-A) isotherm of R-phycoerythrin (R-PE) at
the air-water interface has been measured. The results indicate that
R-PE on form the monomolecular film. Moreover, the molecule-occupied a
rea extrapolating the linear part of the pi-A isotherm is identical wi
th that when an R-PE molecule is located at the interface with its dis
k plane parallel to the air-water interface. The transmission electron
micrograph (TEM) and the measurement of the thickness of the protein
monolayer by ellipsometry show that the orientation of R-PE disk plane
on the substrate is parallel to the plane of substrate. Absorption an
d fluorescence spectra of R-PE LB multilayers were obtained through tr
ansferring R-PE monolayer at the air-water interface to the substrates
at the proper surface pressure by Langmuir-Blodgett (LB) technique. T
hese spectra of R-PE LB film do not show distinct differences from tho
se in aqueous solution. Comparative studies of circular dichroism (CD)
spectra of the protein between in aqueous solution and in LB film sho
w that the changes of the secondary structure of R-PE take place, i.e.
the beta-sheet component of the protein increases in the LB films.