Interrelations of bioenergetic and sensory functions of the retinal proteins

Abstract

Rhodopsins are intrinsic membrane retinal-containing proteins composed of 7 hydrophobic a-helical transmembrane columns and hydrophilic sequences of various length connecting the helices and localized at N- and C-ends of the polypeptide. The chromophore (retinal) forms a Schiff base with a lysine residue in the middle part of the last a-helix. Absorption of a photon results in isomerization of retinal which gives rise to a conformational change in the protein moiety.