Properties of the P-type ATPases encoded by the copAP operons of Helicobacter pylori and Helicobacter felis
Properties of the P-type ATPases encoded by the copAP operons of Helicobacter pylori and Helicobacter felis
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DOI：
10.1128/jb.180.2.317-329.1998
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发表时间：
1998-01-01
影响因子：
3.2
通讯作者：
Melchers, K
中科院分区：
文献类型：
--
作者：
Bayle, D;Wängler, S;Melchers, K
通过基因文库筛选，克隆了幽门螺杆菌和猫科幽门螺杆菌的COP操纵子。这两个操纵子都含有与CD2+和Cu2+ATPase同源的P型离子泵(CopA)的开放阅读框架和一个可能的离子结合蛋白(Copp)，后者代表Hirae肠球菌CopYZAB操纵子的CopZ同源物。预测的CopA-ATPase含有一个N-末端的GMXCXXC离子结合基序和一个膜相关的CPC序列。人工合成的幽门螺杆菌CopA-ATPase N端肽与Cu2+特异性结合，COPA的基因突变导致H.Pylori对Cu2+的生长敏感性增强，但对其他二价阳离子的敏感性不强。如实验所确定的，H.Pylori CopA包含四对跨膜片段(H1至H8)，其中ATP结合和磷酸化结构域位于H6和H7之间，与发现的另一种可能的H.Pylori过渡金属泵一样(K.Melcher，T.Weitzenegger，A.Buhmann，W.Steinhelber，G.Sachs和K.P.Schafer，J.Biol)。化学。271：446-457,1996)。通过疏水性分析和序列相似性分析，鉴定了该泵的相应跨膜片段。为了确定功能结构域，对两种酶的相似定向区域进行了序列同一性检查。高度同源性的区域包括N端的Cu2+结合结构域，能量转导结构域中的ATP结合和磷酸化区域，以及由H4、H6和H7中最后六个半胱氨酸保守的跨膜片段组成的转运域。这些数据表明，幽门螺杆菌和费氏幽门螺杆菌对铜的抗性依赖于ATPase的保守机制。
The cop operons of Helicobacter pylori and Helicobacter felis were cloned by gene library screening. Both operons contain open reading frames for a P-type ion pump (CopA) with homology to Cd2+ and Cu2+ ATPases and a putative ion binding protein (CopP), the latter representing a CopZ homolog of the copYZAB operon of Enterococcus hirae. The predicted CopA ATPases contained an N-terminal GMXCXXC ion binding motif and a membrane-associated CPC sequence. A synthetic N-terminal peptide of the H. pylori CopA ATPase bound to Cu2+ specifically, and gene disruption mutagenesis of CopA resulted in an enhanced growth sensitivity of H. pylori to Cu2+ but not to other divalent cations. As determined experimentally, H. pylori CopA contains four pairs of transmembrane segments (H1 to H8), with the ATP binding and phosphorylation domains lying between H6 and H7, as found for another putative transition metal pump of H. pylori (K. Melchers, T. Weitzenegger, A. Buhmann, W. Steinhilber, G. Sachs, and K. P. Schafer, J. Biol. Chem. 271:446-457, 1996). The corresponding transmembrane segments of the H. felis CopA pump were identified by hydrophobicity analysis and via sequence similarity. To define functional domains, similarly oriented regions of the two enzymes were examined for sequence identity. Regions with high degrees of identity included the N-terminal Cu2+ binding domain, the regions of ATP binding and phosphorylation in the energy transduction domain, and a transport domain consisting of the last six transmembrane segments with conserved cysteines in H4, H6, and H7. The data suggest that H. pylori and H. felis employ conserved mechanisms of ATPase-dependent copper resistance.