Spatial arrangement of rhodopsin in retinal rod outer segment membranes studied by spin-labeling and pulsed electron double resonance

► Use of spin labeling and PELDOR to measure inter-rhodopsin distance in ROS. ► Strong decay of PELDOR signal indicated a high density (mM range) of rhodopsin. ► The decay was modeled by rhodopsin monomers dispersed in a planar membrane.