Hj. Steinhoff et J. Schwemer, SPIN-LABELING ANALYSIS OF STRUCTURE AND DYNAMICS IN OCTOPUS RHODOPSIN, Journal of photochemistry and photobiology.B, Biology, 35(1-2), 1996, pp. 1-6
The location of cysteines accessible in octopus rhodopsin were charact
erized by a spin-labeling technique. Two cysteines were found to bind
a methanthiosulfonate spin label. One of the spin labels is attached t
o helix V with the side chain located within the membrane, most probab
ly close to the polar head group region. The second spin label was fou
nd to be attached to cysteine 345 in the C terminus. Light-induced rev
ersible electron paramagnetic resonance spectral changes were observed
for the spin label attached at position 345. It is concluded that con
formational changes occur during the rhodopsin to metarhodopsin transi
tion in the vicinity of the C-terminus position 345.