TY - JOUR
T1 - The orientation of rhodopsin and other pigments in dry films
AU - Wright, W. E.
AU - Brown, P. K.
AU - Wald, G.
PY - 1972/2/1
Y1 - 1972/2/1
N2 - When rhodopsin in a gelatin film is dried, the rhodopsin chromophores orient primarily in the plane of the film. When the film is wetted, the chromophores disorient. These changes are reversible. When rhodopsin in a wet film is bleached in the presence of hydroxylamine and redried, the retinal oxime which results is oriented more perpendicularly to the plane of the film. These orientations in dry gelatin films resemble those in the disc membranes of rod outer segments. A variety of other proteins are similarly oriented in dry gelatin films: methemoglobin, cytochrome c, phycocyanin. Films of methemoglobin and cytochrome c display prominently the high Soret band near 410 nm when measured with unpolarized light passing through the face of the fim, but display no Soret band at all with light passing through the edge of the film. All of these orientations imply a large asymmetry of the protein micelles, perhaps conferred upon them by linear polymerization in the course of drying. Such asymmetry can be demonstrated directly with rhodopsin. A wet paste of rhodopsindigitonin micelles, sheared between glass slides, becomes highly oriented, the rhodopsin chromophores lining up in the direction of shear, the retinal oxime produced by bleaching orienting more perpendicularly to the shear.
AB - When rhodopsin in a gelatin film is dried, the rhodopsin chromophores orient primarily in the plane of the film. When the film is wetted, the chromophores disorient. These changes are reversible. When rhodopsin in a wet film is bleached in the presence of hydroxylamine and redried, the retinal oxime which results is oriented more perpendicularly to the plane of the film. These orientations in dry gelatin films resemble those in the disc membranes of rod outer segments. A variety of other proteins are similarly oriented in dry gelatin films: methemoglobin, cytochrome c, phycocyanin. Films of methemoglobin and cytochrome c display prominently the high Soret band near 410 nm when measured with unpolarized light passing through the face of the fim, but display no Soret band at all with light passing through the edge of the film. All of these orientations imply a large asymmetry of the protein micelles, perhaps conferred upon them by linear polymerization in the course of drying. Such asymmetry can be demonstrated directly with rhodopsin. A wet paste of rhodopsindigitonin micelles, sheared between glass slides, becomes highly oriented, the rhodopsin chromophores lining up in the direction of shear, the retinal oxime produced by bleaching orienting more perpendicularly to the shear.
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U2 - 10.1085/jgp.59.2.201
DO - 10.1085/jgp.59.2.201
M3 - Article
C2 - 4110154
AN - SCOPUS:0015294374
SN - 0022-1295
VL - 59
SP - 201
EP - 212
JO - Journal of General Physiology
JF - Journal of General Physiology
IS - 2
ER -