Molecular Interactions and Mutational Impact upon Rhodopsin (G90→D90) for Hindering Dark Adaptation of Eye: A Comparative Structural Level Outlook for Signaling Mechanism in Night Blindness

Publication date: Available online 4 January 2019Source: Mutation Research/Fundamental and Molecular Mechanisms of MutagenesisAuthor(s): Arundhati Banerjee, Sujay RayAbstractFor night blindness, a detailed structural exploration of the interactions among G-protein receptor rhodopsin, transducin and arrestin was performed. Rhodopsin is responsible for dim light vision while a point mutation (G90→D90) results in an adverse change in its photo-transduction. The validated 3D models of the three proteins were utilized, and upon mutation and interactions, rhodopsin attained higher stability (evaluated through thermodynamic energy calculations, electrostatic surface potential and solvent accessible area), thereby participating strongly with transducin. Conformational switches in mutated rhodopsin also depicted a firm conformation with few 310 helices accompanied by increased percentage of pure α-helices and sheets. All evaluations were corroborated through paired T-tests. Glu33 (glycosylated unit in the N-terminal zone) of rhodopsin plays a chief role in the overall interaction pattern. Arg69 and Glu33 from wild-type rhodopsin participated in ionic interactions, while the latter set of ionic interaction remained preserved even after mutation. Cys323 (C-terminal residue) and Arg69 formed H-bonds from the wild-type rhodopsin. Cys323 exceptionally supports cellular signaling pattern in the non-mutated situation and for the non-sufferers of night-blindness. Ser297 and Tyr43 from muta...
Source: Mutation Research Fundamental and Molecular Mechanisms of Mutagenesis - Category: Cytology Source Type: research