Secondary binding sites of retinoids in opsin: characterization and role in regeneration.
To regenerate light-sensitive rhodopsin in rods from active metarhodopsin II (Meta II), all-trans-retinal must be removed from the retinal binding pocket and metabolically supplied 11-cis-retinal has to form a new retinylidene bond in the active site. Recent work from this laboratory has focused on Meta II decay and release and uptake of retinals in opsin employing intrinsic protein fluorescence. Here we summarize the results in the retinal channeling hypothesis, which describes a passage of the chromophore through the protein. 11-cis-retinal is taken up into an entrance site, and photolyzed all-trans-retinal is released from the active site into an exit site.
Heck
Martin
M
Institut für Medizinische Physik und Biophysik, Universitätsklinikum Charité, Humboldt Universität zu Berlin, Schumannstr. 20-21, 10098 Berlin, Germany.
Schädel
Sandra A
SA
Maretzki
Dieter
D
Hofmann
Klaus Peter
KP
D001665:Binding Sites; D006801:Humans; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism*; D012172:Retinaldehyde / Q000378:metabolism; D012176:Retinoids / Q000378:metabolism*; D012243:Rhodopsin / Q000031:analogs & derivatives* / Q000378:metabolism; D017299:Rod Opsins / Q000378:metabolism*
D012176:Retinoids; D017299:Rod Opsins; C013110:metarhodopsins; D012243:Rhodopsin; D012172:Retinaldehyde