Calcium-dependent conformational changes in guanylate cyclase-activating protein 2 monitored by cysteine accessibility
Calcium-dependent conformational changes in guanylate cyclase-activating protein 2 monitored by cysteine accessibility
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DOI：
10.1016/j.bbrc.2007.03.023
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发表时间：
2007-05-11
影响因子：
3.1
通讯作者：
Koch, Karl-Wilhelm
中科院分区：
文献类型：
--
作者：
Helten, Andreas;Koch, Karl-Wilhelm
鸟苷酸环化酶激活蛋白2（GCAP 2）在脊椎动物光感受器细胞中表达，其中它以Ca 2+依赖性方式调节膜结合鸟苷酸环化酶的活性。基本的触发步骤涉及Ca 2+诱导的GCAP 2构象变化。我们通过用巯基修饰试剂5，5 '-二硫代-双-（2-硝基苯甲酸）（DTNB）探测野生型和突变型GCAP 2形式中的半胱氨酸可及性来研究这些Ca 2+依赖性变化。在Ca 2+存在下，35和111位的半胱氨酸残基显示出有限的可及性，而在Ca 2+存在和不存在下，131位的半胱氨酸与DTNB反应。我们的数据表明，GCAP 2的钙敏感性显着控制其第三个钙结合位点，EF手3。(c)2007年爱思唯尔公司All rights reserved.
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 5,5'-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. (c) 2007 Elsevier Inc. All rights reserved.