Anisotropic optical constants of bacteriorhodopsin in the mid-infrared:: Consequence on the determination of α-helix orientation

被引:29
作者
Blaudez, D
Boucher, F
Buffeteau, T
Desbat, B
Grandbois, M
Salesse, C
机构
[1] Univ Bordeaux 1, Lab Phys Chim Mol, UMR 5803, F-33405 Talence, France
[2] Univ Quebec, Dept Chim Biol, GREIB, Trois Rivieres, PQ G9A 5H7, Canada
[3] Univ Bordeaux 1, Ctr Phys Mol Opt & Hertzienne, UMR 5798, F-33405 Talence, France
关键词
infrared; optical constants; protein; bacteriorhodopsin monolayer; PM-IRRAS; air/water interface; ATR;
D O I
10.1366/0003702991945551
中图分类号
TH7 [仪器、仪表];
学科分类号
0804 ; 080401 ; 081102 ;
摘要
In this paper, we present the first determination of the anisotropic optical constants of a protein (bacteriorhodopsin or bR) monolayer in the mid-infrared range. This procedure has allowed us to calculate a mean tilt angle of the alpha-helices' axis with respect to the normal of the surface, Using these optical constants, we have been able to reproduce the polarized attenuated total reflection (ATR) spectra of a bR monolayer deposited on a germanium crystal, On the other hand, the optical constants have to be modified to reproduce the polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS) spectrum of a bR monolayer spread at the air/water interface. This modification of the optical constants indicates that the a helices are more tilted when the bR monolayer is spread on the water surface than when it is deposited onto a dry solid substrate.
引用
收藏
页码:1299 / 1304
页数:6
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