Mapping of the amino acids in the cytoplasmic loop connecting helices C and D in rhodopsin: chemical reactivity in the dark state following single cysteine replacements

The role of the structure in the cytoplasmic loop which corrects helices C and D rhodopsin, a part involved in protein-protein interactions during signal transduction, in the reactivity of the successive cysteine residues is demonstrated. This has been done by replacing, one at a time, the amino acids 136-150 by cysteine residues. The results show differences in both the reactivity and accessibility of the different cysteine residues in the CD loop.