Abstract
Guanylate cyclase-activating protein 1 (GCAP-1) is a Ca 2+-sensing protein in vertebrate photoreceptor cells. It activates a membrane-bound guanylate cyclase. Three of four cysteines present in wild-type GCAP-1 were accessible to the thiol-modifying reagent 5,5′-dithio-bis-(2-nitrobenzoic acid) in the presence of Ca 2+. Only Cys106 became exposed to the solvent after Ca 2+-chelation. Since Cys106 is located in EF-hand 3, we could determine an apparent K D of 2.9 μM for Ca 2+ binding to this site with a fast off-rate ( t∼2 ms). We conclude that the rapid dissociation of Ca 2+ from EF-hand 3 in GCAP-1 triggers activation of guanylate cyclase in rod cells.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
