TY - JOUR TI - Spontaneous activation of visual pigments in relation to openness/closedness of chromophore-binding pocket AU - Yue, Wendy Wing Sze AU - Frederiksen, Rikard AU - Ren, Xiaozhi AU - Luo, Dong-Gen AU - Yamashita, Takahiro AU - Shichida, Yoshinori AU - Cornwall, M Carter AU - Yau, King-Wai A2 - Aldrich, Richard VL - 6 PY - 2017 DA - 2017/02/10 SP - e18492 C1 - eLife 2017;6:e18492 DO - 10.7554/eLife.18492 UR - https://doi.org/10.7554/eLife.18492 AB - Visual pigments can be spontaneously activated by internal thermal energy, generating noise that interferes with real-light detection. Recently, we developed a physicochemical theory that successfully predicts the rate of spontaneous activity of representative rod and cone pigments from their peak-absorption wavelength (λmax), with pigments having longer λmax being noisier. Interestingly, cone pigments may generally be ~25 fold noisier than rod pigments of the same λmax, possibly ascribed to an ‘open’ chromophore-binding pocket in cone pigments defined by the capability of chromophore-exchange in darkness. Here, we show in mice that the λmax-dependence of pigment noise could be extended even to a mutant pigment, E122Q-rhodopsin. Moreover, although E122Q-rhodopsin shows some cone-pigment-like characteristics, its noise remained quantitatively predictable by the ‘non-open’ nature of its chromophore-binding pocket as in wild-type rhodopsin. The openness/closedness of the chromophore-binding pocket is potentially a useful indicator of whether a pigment is intended for detecting dim or bright light. KW - visual pigment KW - spontaneous excitation KW - retinal photoreceptors KW - vision JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -