Calcium-dependent cysteine reactivities in the neuronal calcium sensor guanylate cyclase-activating protein 1

Citation
Jy. Hwang et al., Calcium-dependent cysteine reactivities in the neuronal calcium sensor guanylate cyclase-activating protein 1, FEBS LETTER, 508(3), 2001, pp. 355-359
Citations number
18
Categorie Soggetti
Biochemistry & Biophysics
Journal title
FEBS LETTERS
ISSN journal
00145793 → ACNP
Volume
508
Issue
3
Year of publication
2001
Pages
355 - 359
Database
ISI
SICI code
0014-5793(20011123)508:3<355:CCRITN>2.0.ZU;2-Q
Abstract
Guanylate cyclase-activating protein 1 (GCAP-1) is a Ca2+-sensing protein i n vertebrate photoreceptor cells. It activates a membrane-bound guanylate c yclase. 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 th e presence of Ca2+. Only Cys106 became exposed to the solvent after Ca2+-ch elation. Since Cys106 is located in EF-hand 3, we could determine an appare nt K-D of 2.9 muM for Ca2+ binding to this site with a fast off-rate (t sim ilar to2 ms). We conclude that the rapid dissociation of Ca2+ from EF-hand 3 in GCAP-1 triggers activation of guanylate cyclase in rod cells. (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Scienc e B.V. All rights reserved.