Partial solid-state NMR 1H, 13C, 15N resonance assignments of a perdeuterated back-exchanged seven-transmembrane helical protein Anabaena Sensory Rhodopsin

Anabaena Sensory Rhodopsin (ASR) is a unique photochromic membrane-embedded photosensor which interacts with soluble transducer and is likely involved in a light-dependent gene regulation in the cyanobacterium Anabaena sp. PCC 7120. We report partial spectroscopic ¹H, ¹³C and ¹⁵N assignments of perdeuterated and back-exchanged ASR reconstituted in lipids. The reported assignments are in general agreement with previously determined assignments of carbon and nitrogen resonances in fully protonated samples. Because the back-exchange was performed on ASR in a detergent-solubilized state, the location of detected residues reports on the solvent accessibility of ASR in detergent. A comparison with the results of previously published hydrogen/exchange data collected on the ASR reconstituted in lipids, suggests that the protein has larger solvent accessible surface in the detergent-solubilized state.