Direct determination of a molecular torsional angle in the membrane protein rhodopsin by solid-state NMR

A solid-state NMR technique was applied to a super13Csub2 labeled sample of the 41kD integral membrane protein rhodopsin, under magic-angle-spinning conditions. The technique allows good sensitivity and resolution, and enables a direct determination of molecular torsional angles. It was determined that the H-C10-C11-H torsional angle of the rentinylidene chromophore in rhodopsin was 160 plus or minus 10 deg.