Structural and energetic analysis of activation by a cyclic nucleotide binding domain
Structural and energetic analysis of activation by a cyclic nucleotide binding domain
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DOI：
10.1016/j.jmb.2008.06.011
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发表时间：
2008-09-05
影响因子：
5.6
通讯作者：
Morais-Cabral, Joao H.
中科院分区：
文献类型：
--
作者：
Altieri, Stephen L.;Clayton, Gina M.;Morais-Cabral, Joao H.
MlotiK1是环核苷酸依赖离子通道的原核同源物，包含胞内c端环核苷酸结合（CNB）结构域。在没有配体和与cAMP结合的情况下，CNB结构域的x射线结构得到了求解。全长通道和CNB结构域片段都很容易表达和纯化，使MlotiK1成为一个有用的模型系统，用于解剖配体结合激活。我们使用x射线晶体学确定了三种新的MlotiK1 CNB结构域结构：第二apo结构，cgmp结合结构和第二camp结合结构。结合起来，这五个MlotiK1 CNB结构域结构提供了一个独特的机会来分析单个蛋白质中载脂蛋白状态和结合状态之间的结构差异，以及每种状态下的结构可变性。以这一分析为指导，我们探讨了特定残基侧链在配体结合和通道激活中的核苷酸选择性和重要性。这些数据有助于确定配体-蛋白质相互作用，这对MlotiK1配体依赖性很重要，更广泛地说，对核苷酸依赖性蛋白类也很重要。(C) 2008 Elsevier Ltd版权所有。
MlotiK1 is a prokaryotic homolog of cyclic-nucleotide-dependent ion channels that contains an intracellular C-terminal cyclic nucleotide binding (CNB) domain. X-ray structures of the CNB domain have been solved in the absence of ligand and bound to cAMP. Both the full-length channel and CNB domain fragment are easily expressed and purified, making MlotiK1 a useful model system for dissecting activation by ligand binding. We have used Xray crystallography to determine three new MlotiK1 CNB domain structures: a second apo configuration, a cGMP-bound structure, and a second cAMP-bound structure. In combination, the five MlotiK1 CNB domain structures provide a unique opportunity for analyzing, within a single protein, the structural differences between the apo state and the bound state, and the structural variability within each state. With this analysis as a guide, we have probed the nucleotide selectivity and importance of specific residue side chains in ligand binding and channel activation. These data help to identify ligand-protein interactions that are important for ligand dependence in MlotiK1 and, more globally, in the class of nucleotide-dependent proteins. (C) 2008 Elsevier Ltd. All rights reserved.