Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1937865 | Biochemical and Biophysical Research Communications | 2007 | 6 Pages |
Abstract
Guanylate cyclase-activating protein 2 (GCAP2) is expressed in vertebrate photoreceptors cells where it regulates the activity of membrane bound guanylate cyclases in a Ca2+-dependent manner. The essential trigger step involves a Ca2+-induced conformational change in GCAP2. We investigated these Ca2+-dependent changes by probing the cysteine accessibility in wild type and mutant GCAP2 forms with the thiol-modifying reagent 5,5â²-dithio-bis-(2-nitrobenzoic acid) (DTNB). Cysteine residues in position 35 and 111 displayed a restricted accessibility in the presence of Ca2+, whereas cysteine in position 131 reacted with DTNB in the presence and absence of Ca2+. Our data indicate that the Ca2+-sensitivity of GCAP2 is significantly controlled by its third Ca2+-binding site, EF-hand 3.
Keywords
DTTGCAPNCSDTNB5,5′-dithio-bis-(2-nitrobenzoic acid)EF-handROSSDS–PAGEsodium dodecyl sulfate–polyacrylamide gel electrophoresisPhototransductiondithiothreitolneuronal calcium sensorrod outer segmentswild typeCa2+-binding proteinGuanylate cyclase-activating proteinhigh performance liquid chromatographyHPLC
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Authors
Andreas Helten, Karl-Wilhelm Koch,