Drees Steffen L, Beyer Dominik F, Lenders-Lomscher Christina, Lübben Mathias
Department of Biophysics, Ruhr University Bochum, Universitätsstr. 150, D-44801, Bochum, Germany.
Mol Microbiol. 2015 Aug;97(3):423-38. doi: 10.1111/mmi.13038. Epub 2015 May 20.
P1 B -ATPases are among the most common resistance factors to metal-induced stress. Belonging to the superfamily of P-type ATPases, they are capable of exporting transition metal ions at the expense of adenosine triphosphate (ATP) hydrolysis. P1 B -ATPases share a conserved structure of three cytoplasmic domains linked by a transmembrane domain. In addition, they possess a unique class of domains located at the N-terminus. In bacteria, these domains are primarily associated with metal binding and either occur individually or as serial copies of each other. Within this study, the roles of the two adjacent metal-binding domains (MBDs) of CopA, the copper export ATPase of Escherichia coli were investigated. From biochemical and physiological data, we deciphered the protein-internal pathway of copper and demonstrate the distal N-terminal MBD to possess a function analogous to the metallochaperones of related prokaryotic copper resistance systems, that is its involvement in the copper transfer to the membrane-integral ion-binding sites of CopA. In contrast, the proximal domain MBD2 has a regulatory role by suppressing the catalytic activity of CopA in absence of copper. Furthermore, we propose a general functional divergence of tandem MBDs in P1 B -ATPases, which is governed by the length of the inter-domain linker.
P1 B型ATP酶是金属诱导应激最常见的抗性因子之一。它们属于P型ATP酶超家族，能够以三磷酸腺苷（ATP）水解为代价输出过渡金属离子。P1 B型ATP酶具有由跨膜结构域连接的三个细胞质结构域的保守结构。此外，它们在N端拥有一类独特的结构域。在细菌中，这些结构域主要与金属结合相关，要么单独出现，要么彼此串联复制。在本研究中，对大肠杆菌铜输出ATP酶CopA的两个相邻金属结合结构域（MBD）的作用进行了研究。从生化和生理数据中，我们解析了铜在蛋白质内部的运输途径，并证明远端N端MBD具有与相关原核铜抗性系统的金属伴侣类似的功能，即它参与将铜转移到CopA的膜整合离子结合位点。相比之下，近端结构域MBD2在没有铜的情况下通过抑制CopA的催化活性发挥调节作用。此外，我们提出了P1 B型ATP酶中串联MBD的一般功能差异，这由结构域间连接子的长度决定。
