COMPARISON OF BACTERIORHODOPSIN CONFORMATIONAL-CHANGES WITH UNIAXIALLY ELONGATED ALIPHATIC POLYAMIDE SAMPLES BY USING FT-IR DIFFERENCE SPECTROSCOPY

FT-IR difference spectra for the photoreactions of bacteriorhodopsin ( bR) are compared to difference spectra of polyamide-6 and -11 obtained during uniaxial elongation. The purple membrane was hydrated with D2O in order to identify bands above 3000 cm(-1) In the bR photocycle(bR --> K), the difference spectra in D2O closely march the band contour f ound in the difference spectra of elongated polyamide-11. The data sug gest that a structural change occurs in the backbone of the membrane p rotein bacteriorhodopsin, resulting in weakened and strengthened hydro gen bonds of the amide functionality of the backbone.