Variability of calcium binding to EF-hand motifs probed by electrospray ionization mass spectrometry
Variability of calcium binding to EF-hand motifs probed by electrospray ionization mass spectrometry
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DOI：
10.1016/s1044-0305(01)00317-8
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发表时间：
2001-12-01
影响因子：
3.2
通讯作者：
Murthy, MRN
中科院分区：
文献类型：
--
作者：
Moorthy, AK;Singh, SK;Murthy, MRN
采用质谱法研究了溶组织内阿米巴钙结合蛋白（CaBP）钙调素（CAM）同源物中EF-手状结构对钙结合的调节作用，并研究了pH、配体配位剂EGTA和碎裂电压对CaBP钙结合的影响。钙结合在高酸性和碱性pH下遵循预期模式，分别以载脂蛋白和完全饱和形式为主。令人惊讶的是，额外的非特异性结合观察到接近中性pH值。EGTA螯合和fragmentor电压的影响的研究表明，在至少一个域中的钙去除的协同性。类似的研究一个较小的结构，含有两个高亲和力的羧基末端位点揭示了有趣的差异，并提供了一个估计的特异性和耐受性的EF-手图案钙结合和去除。(C)2001年美国质谱学会。
The modulation of calcium binding by the EF-hand motifs present in a calmodulin (CAM) homologue, a calcium binding protein (CaBP) from Entamoeba histolytica by three external parameters-pH, ligand coordinator EGTA, and fragmentor voltage was investigated by mass spectrometry. Calcium binding follows expected patterns at highly acidic and alkaline pH with the preponderance of the apo and the completely saturated forms, respectively. Surprisingly, additional nonspecific binding is observed near neutral pH. Studies on EGTA chelation and effects of fragmentor voltage showed cooperativity in calcium removal in at least one of the domains. Similar studies on a smaller construct containing the two high affinity carboxy terminal sites revealed interesting differences and provided an estimate of the specificity and tolerance of the EF-hand motifs to calcium binding and removal. (C) 2001 American Society for Mass Spectrometry.