title: A methyl group at C7 of 11-cis-retinal allows chromophore formation but affects rhodopsin activation.
abstract: The newly synthesized 11-cis-7-methylretinal can form an artificial visual pigment with kinetic and spectroscopic properties similar to the native pigment in the dark-state. However, its photobleaching behavior is altered, showing a Meta I-like photoproduct. This behavior reflects a steric constraint imposed by the 7-methyl group that affects the conformational change in the binding pocket as a result of retinal photoisomerization. Transducin activation is reduced, when compared to the native pigment with 11-cis-retinal. Molecular dynamics simulations suggest coupling of the C7 methyl group and the beta-ionone ring with Met207 in transmembrane helix 5 in agreement with recent experimental results.
authors.affiliation: Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, 08222 Terrassa, Catalonia, Spain.
authors.forename: Laia
authors.initials: L
authors.lastname: Bosch
authors.forename: Arnau
authors.initials: A
authors.lastname: Cordomí
authors.forename: Marta
authors.initials: M
authors.lastname: Domínguez
authors.forename: Darwin
authors.initials: D
authors.lastname: Toledo
authors.forename: Margarita
authors.initials: M
authors.lastname: Morillo
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Pérez
authors.forename: Rosana
authors.initials: R
authors.lastname: Alvarez
authors.forename: Angel R
authors.initials: AR
authors.lastname: de Lera
authors.forename: Pere
authors.initials: P
authors.lastname: Garriga
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D003198:Computer Simulation; D003623:Dark Adaptation; D004224:Diterpenes; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D011485:Protein Binding; D012172:Retinaldehyde / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D012243:Rhodopsin / Q000378:metabolism*; D012374:Rod Cell Outer Segment / Q000378:metabolism*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D015293:Transducin / Q000378:metabolism*; D014785:Vision, Ocular / Q000502:physiology
chemical_list: C516946:7-methylretinal; C516945:8-methylretinal; D004224:Diterpenes; D012243:Rhodopsin; D019204:GTP-Binding Proteins; D015293:Transducin; D012172:Retinaldehyde