title: Bicycle-pedal model for the first step in the vision process.
abstract: Computer simulation of the molecular dynamics of retinal during its photoisomerisation inside a restrictive active site gives a detailed model for the sequence of events in the first step of the vision process. It is proposed that the prelumirhodopsin intermediate contains a strained all-trans retinal molecule produced directly and rapidly from the 11-cis, 12-s-trans conformation in rhodopsin by a bicycle-pedal isomerisation. The model reproduces the main experimental observations and explains how the protein makes the photoisomerisation path unique.
mesh_terms: D001665:Binding Sites; D055598:Chemical Phenomena; D002621:Chemistry; D008954:Models, Biological; D008968:Molecular Conformation; D010777:Photochemistry; D011487:Protein Conformation; D012168:Retinal Pigments; D012172:Retinaldehyde; D012243:Rhodopsin; D012542:Scattering, Radiation; D012545:Schiff Bases; D013057:Spectrum Analysis; D013237:Stereoisomerism; D014785:Vision, Ocular; D014801:Vitamin A / Q000031:analogs & derivatives
chemical_list: D012168:Retinal Pigments; D012545:Schiff Bases; D014801:Vitamin A; D012243:Rhodopsin; D012172:Retinaldehyde