Circular dichroism, optical rotatory dispersion, and absorption studies on the conformation of bovine rhodopsin in situ and solubilized with detergent

Formation and properties of bacteriorhodopsin monomers in the non‐ionic detergents octyl‐β‐D‐glucoside and triton X‐100

“…No positive 'monomer' band could be detected however when solubilization was complete. It is well known in the case of solubilized rhodopsin that the amplitude of the intrinsic CD varies with different detergents [6] , From the disappearance of the exciton coupling effects we conclude that solubilization into monomers occurs. This conclusion was confirmed by a determination of the Stokes radius of the bacteriorhodopsin-lipid-octylglucoside micelle.…”

“…Whereas the hexagonally aggregated state of the protein is characterized by an exciton CD spectrum, the monomeric state is characterized by a positive CD band centered at the absorption maximum [5]. A similar 'monomer' or intrinsic CD band is also observed with monomeric rhodopsin [6].…”

Differentiation between transmembrane helices and peripheral helices by the deconvolution of circular dichroism spectra of membrane proteins

“…The CD spectra were measured as described in the Materials and methods and in the legend in ( t t in Fig. 4) forms of rhodopsin showed little difference, which was not unexpected according to a systematic study of the two forms in various detergents by Rafferty et al (1977), where the two forms showed differences in CD spectra when a detergent destabilized the protein. Therefore, if a detergent is sufficiently mild that it does not affect the conformational stability, it was expected that the two forms would not show any difference in the CD spectra.…”

“…The decomposition result for PM was that expected, in that the a-helical content was underestimated by the VS method (53%) but overestimated by the Yang method (76.5%), in comparison with 66% a helix determined by EM (Henderson et al, 1990), with small amounts of 0 strands (16% by VS method, and 0% by Yang method). There are, however, no compatible data for rhodopsin for the evaluation of the decomposition results or the CD spectrum itself, because the CD spectra reported in Rafferty et al (1977) were not corrected for molecular weight. The a-helical content in this case is higher than reported, which was about 30% (Rafferty et al, 1977).…”

“…There are, however, no compatible data for rhodopsin for the evaluation of the decomposition results or the CD spectrum itself, because the CD spectra reported in Rafferty et al (1977) were not corrected for molecular weight. The a-helical content in this case is higher than reported, which was about 30% (Rafferty et al, 1977).…”