Rod photoreceptors detect single photons through a tradeoff of light collecting ability, amplification and speed. Key roles are played by rhodopsin (Rh) and transducin (Gt), whose complex supramolecular organization in outer segment disks begs for a functional interpretation. Here we review past and recent evidence of a temperature-dependence of photon detection by mammalian rods, and link this phenomenon with the putative oligomeric organization of Rh and new ideas on the dynamics of Rh-Gt interaction. Identifying an electrophysiological correlate of the supramolecular organization of Rh and Gt may shed light on the evolutionary advantage it confers to night vision.
Detecting single photons: A supramolecular matter?
DELL'ORCO, Daniele
2013
Abstract
Rod photoreceptors detect single photons through a tradeoff of light collecting ability, amplification and speed. Key roles are played by rhodopsin (Rh) and transducin (Gt), whose complex supramolecular organization in outer segment disks begs for a functional interpretation. Here we review past and recent evidence of a temperature-dependence of photon detection by mammalian rods, and link this phenomenon with the putative oligomeric organization of Rh and new ideas on the dynamics of Rh-Gt interaction. Identifying an electrophysiological correlate of the supramolecular organization of Rh and Gt may shed light on the evolutionary advantage it confers to night vision.
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