Matsushika A, Mizuno T
Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Chikusa-ku, Nagoya, 464-8601, Japan.
J Biochem. 1998 Aug;124(2):440-5. doi: 10.1093/oxfordjournals.jbchem.a022132.
The Escherichia coli ArcB sensor is involved in anaerobic signal transduction. ArcB is an unorthodox His-kinase, in that it contains three types of phosphotransfer signaling domains in its primary amino acid sequence, namely, transmitter (or His-kinase), receiver, and histidine-containing phosphotransfer (HPt) domains. In this study, we first conducted an in vivo experiment to determine whether or not the phosphorylation of the HPt domain is crucial for ArcB/ArcA-mediated anaerobic signal transduction. The results are best interpreted as meaning that the HPt domain of ArcB is important for the anaerobic signal transduction, as far as the expression of the succinate dehydrogenase (sdh) operon is concerned. We then isolated a set of ArcB mutant each with a single amino acid substitution in the HPt domain, which has lost the ability to function as a phospho-transmitter. The results of such mutational analyses, together with the three-dimensional crystal structure of the HPt domain, provided an insight into the structure and function of the HPt domain of ArcB.
大肠杆菌ArcB传感器参与厌氧信号转导。ArcB是一种非传统的组氨酸激酶，因为它在其一级氨基酸序列中包含三种类型的磷酸转移信号结构域，即发射器（或组氨酸激酶）、接收器和含组氨酸的磷酸转移（HPt）结构域。在本研究中，我们首先进行了一项体内实验，以确定HPt结构域的磷酸化对于ArcB/ArcA介导的厌氧信号转导是否至关重要。就琥珀酸脱氢酶（sdh）操纵子的表达而言，结果最好解释为ArcB的HPt结构域对厌氧信号转导很重要。然后，我们分离出一组在HPt结构域中具有单个氨基酸取代的ArcB突变体，这些突变体已经失去了作为磷酸发射器的功能。这些突变分析的结果，连同HPt结构域的三维晶体结构，为ArcB的HPt结构域的结构和功能提供了深入了解。
