Detection of Ca2+‐dependent cyclic GMP binding protein in frog rod outer segments

[摘要]

For the identification of the cGMP-sensitive ion channel protein of frog rod outer segments (ROS), we analyzed cGMP binding proteins in the ROS by photoaffinity labeling with [³H]cGMP. We found three cGMP binding polypeptides (66 kDa, 92 kDa and 100 kDa) in the membrane protein fraction of ROS. cGMP binding to the 66 kDa polypeptide required the addition of 2 mM CaCl₂. We propose that this polypeptide corresponds to the cGMP-activated channel protein reported by Cook et al. [(1987) Proc. Natl. Acad. Sci. USA 84, 585–589]. The 100 kDa and 92 kDa polypeptides are subunits of the cGMP phosphodiesterase.

[学科分类] 生物化学/生物物理

[关键词] Photoreceptor;Rod outer segment;cyclic GMP binding protein;Visual transduction;ROS;rod outer segments;UV254;ultraviolet light at 254 nm;DTT;dithiothreitol;SDS-PAGE;SDS-polyacrylamide gel electrodes