Metal binding discrimination of the calmodulin Q41C/K75C mutant on Ca^(2+) and La^(3+)
Metal binding discrimination of the calmodulin Q41C/K75C mutant on Ca^(2+) and La^(3+)作者机构：State Key Laboratory for Natural and Biomimetic Drugs Peking University Health Science Center Beijing China Department of Chemical Biology School of Pharmaceutical Sciences Peking University Health Science Center Beijing China
出 版 物：《Science China Chemistry》 (中国科学（化学英文版）)
年 卷 期：2010年第53卷第4期
页 面：797-806页
核心收录：
学科分类：0710[理学-生物学] 071010[理学-生物化学与分子生物学] 081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术]
基 金：support from the National Natural Science Foundation of China (Grant Nos. 20671008 & 20637010) the Key Construction Program of the National "985" Project
主 题：calmodulin lanthanum calcium long range interaction
摘 要：Calmodulin (CaM) is a multifunctional Ca2+-binding protein regulating the activity of many enzymes in response to fluctuation of the intracellular Ca2+ level. It has been shown that a CaM Q41C/K75C mutant (CaMSS) with a disulfide bond in the N-terminal domain exhibits greatly reduced affinity to Ca2+. In the present study, the experimental results revealed a unique metal binding pattern in CaMSS towards La3+ and Ca2+ separately: the mutant protein binds Ca2+ at site Ⅰ, Ⅲ and IV; however, it binds La3+ at site Ⅰ, Ⅱ and IV. A putative mechanism was proposed which is the conformation of site Ⅱ (or siteⅢ) of CaMSS could be altered and thus loses its metal ion affinity in response to metal binding in the opposite terminal domain possibly through the long range domain interaction. The present work may offer new perspectives for understanding the mechanisms of specific metal ion affinity in CaM and for CaM-based protein design.
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