Nixon B Tracy, Yennawar Hemant P, Doucleff Michaeleen, Pelton Jeffrey G, Wemmer David E, Krueger Susan, Kondrashkina Elena
Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Biochemistry. 2005 Oct 25;44(42):13962-9. doi: 10.1021/bi051129u.
Two-component signal transduction is the predominant information processing mechanism in prokaryotes and is also present in single-cell eukaryotes and higher plants. A phosphorylation-based switch is commonly used to activate as many as 40 different types of output domains in more than 6000 two-component response regulators that can be identified in the sequence databases. Previous biochemical and crystallographic studies showed that phosphorylation of the two-component receiver domain of DctD causes a switch between alternative dimeric forms, but it was unclear from the crystal lattice of the activated protein precisely which of four possible dimeric configurations is the biologically relevant one [Park, S., et al. (2002) FASEB J. 16, 1964-1966]. Here we report solution structures of the apo and activated DctD receiver domain derived from small angle scattering data. The apo dimer closely resembles that seen in the crystal structure, and the solution data for the activated protein eliminate two of the possible four dimeric conformations seen in the crystal lattice and strongly implicate one as the biologically relevant structure. These results corroborate the previously proposed model for how receiver domains regulate their downstream AAA+ ATPase domains.
双组分信号转导是原核生物中主要的信息处理机制，在单细胞真核生物和高等植物中也存在。基于磷酸化的开关通常用于激活序列数据库中可识别的6000多种双组分响应调节因子中的多达40种不同类型的输出结构域。先前的生化和晶体学研究表明，DctD的双组分接收结构域的磷酸化会导致替代二聚体形式之间的转换，但从活化蛋白的晶格中尚不清楚四种可能的二聚体构型中哪一种是生物学上相关的构型[Park, S., 等人 (2002) FASEB J. 16, 1964 - 1966]。在此，我们报告了从小角散射数据得出的脱辅基和活化的DctD接收结构域的溶液结构。脱辅基二聚体与晶体结构中所见的非常相似，活化蛋白的溶液数据排除了晶格中所见的四种可能二聚体构象中的两种，并强烈暗示其中一种是生物学上相关的结构。这些结果证实了先前提出的关于接收结构域如何调节其下游AAA + ATPase结构域的模型。
