Study of the photocycle of the metastable states of SRII and their mutants with the use of light activated NMR spectroscopy

Sensory rhodopsin II (SRII) is a seven-helix protein that belongs to the rhodopsin protein family. Light-induced conformational changes govern SRII’s function. These changes are related to the photo cycle of the protein that is comprised of various metastable states. After the completion of this cycle the protein returns to its ground state. Mutational studies of key residues will reveal the mechanism that underlies the function of the protein. The result will allow us to determine key structures at various PHs involved in the photo cycle of SRII and to understand the protein’s function and mechanism. 1. Subject and aims. The seven-helix rhodopsin proteins, is a family of membrane proteins that contain retinal as a chromophore and sensory rhodopsin II (SRII) is a member of this class. The members of this family that function as proton pumps and as photoreceptors have been studied. Examples of such proteins are proteorhodopsin1, bacteriorhodopsin2 and sensory SRII (also known as phoborhodopsin3). SRII is a protein that has been studied by various laboratories. A short literaturereview with the most important publications in the field will be described. The structure of the protein was solved