Crystallographic Study of the LUMI Intermediate of Squid Rhodopsin

Upon absorption of light, the retinal chromophore in rhodopsin isomerizes from the 11-cis to the trans configuration, initiating a photoreaction cycle. The primary photoreaction state, bathorhodopsin (BATHO), relaxes thermally through lumirhodopsin (LUMI) into a photoactive state, metarhodopsin (META), which stimulates the conjugated G-protein. Previous crystallographic studies of squid and bovine rhodopsins have shown that the structural change...