AI Article Synopsis
- Binding of arrestin to activated rhodopsin is crucial for stopping the signal amplification in photoreceptor cells.
- While the structures of unbound rhodopsin and arrestin have been identified, the complex structure of rhodopsin bound to arrestin remains unknown.
- Recent studies reveal that a specific peptide in arrestin mimics a part of the protein that recognizes rhodopsin and can bind both phosphorylated and unphosphorylated forms, stabilizing an intermediate state during the process.
Article Abstract
Binding of arrestin to photoactivated phosphorylated rhodopsin terminates the amplification of visual signals in photoreceptor cells. Currently, there is no crystal structure of a rhodopsin-arrestin complex available, although structures of unbound rhodopsin and arrestin have been determined. High-affinity receptor binding is dependent on distinct arrestin sites responsible for recognition of rhodopsin activation and phosphorylation. The loop connecting beta-strands V and VI in rod arrestin has been implicated in the recognition of active rhodopsin. We report the structure of receptor-bound arrestin peptide Arr(67-77) mimicking this loop based on solution NMR data. The peptide binds photoactivated rhodopsin in the unphosphorylated and phosphorylated form with similar affinities and stabilizes the metarhodopsin II photointermediate. A largely alpha-helical conformation of the receptor-bound peptide is observed.
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| http://dx.doi.org/10.1021/bi900544p | DOI Listing |
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