Salt-driven equilibrium between two conformations in the HAMP domain from Natronomonas pharaonis -: The language of signal transfer?
Salt-driven equilibrium between two conformations in the HAMP domain from Natronomonas pharaonis -: The language of signal transfer?
复制标题
DOI：
10.1074/jbc.m801931200
复制
发表时间：
2008-10-17
影响因子：
4.8
通讯作者：
Steinhoff, Heinz-Juergen
中科院分区：
文献类型：
--
作者：
Doebber, Meike;Bordignon, Enrica;Steinhoff, Heinz-Juergen
HAMP结构域(保守于组氨酸激酶、腺苷环化酶、甲基趋化蛋白和磷酸酶)在多种环境中作为信号转导单位在各种蛋白质家族中发挥作用。本文采用定点自旋标记电子顺磁共振技术，研究了环境因素(即盐和温度)对海洋水生单胞菌(Natronomonas Pharaonis)与感觉性视紫红质II(NpSRII)复合体HAMP结构域结构和功能的影响。在NpHtrII(157)中设计了一系列自旋标记突变体，NpHtrII(157)是一个截断的类似物，只包含跨膜螺旋2之后的第一个HAMP结构域。这个截断的换能器被证明是一个有效的信号转导结构域的模型系统，锚定在跨膜光传感器NpSRII上。HAMP结构域被发现在高动态(DHAMP)和更紧凑(CHAMP)构象之间处于“两态”平衡。通过迁移率、可及性和转化器内二聚体距离数据证明了CHAMP的结构特性，该结构与来自Archaeoglobus fulgidus的HAMP结构域的四螺旋束核磁共振模型一致。
HAMP domains (conserved in histidine kinases, adenylyl cyclases, methyl-accepting chemotaxis proteins, and phosphatases) perform their putative function as signal transducing units in diversified environments in a variety of protein families. Here the conformational changes induced by environmental agents, namely salt and temperature, on the structure and function of a HAMP domain of the phototransducer from Natronomonas pharaonis (NpHtrII) in complex with sensory rhodopsin II (NpSRII) were investigated by site-directed spin labeling electron paramagnetic resonance. A series of spin labeled mutants were engineered in NpHtrII(157), a truncated analog containing only the first HAMP domain following the transmembrane helix 2. This truncated transducer is shown to be a valid model system for a signal transduction domain anchored to the transmembrane light sensor NpSRII. The HAMP domain is found to be engaged in a "two-state" equilibrium between a highly dynamic (dHAMP) and a more compact (cHAMP) conformation. The structural properties of the cHAMP as proven by mobility, accessibility, and intra-transducer-dimer distance data are in agreement with the four helical bundle NMR model of the HAMP domain from Archaeoglobus fulgidus.