Reyes Angélica, Leiva Andrea, Cambiazo Verónica, Méndez Marco A, González Mauricio
Laboratorio de Bioinformática y Expresión Génica, INTA, Universidad de Chile.
Biol Res. 2006;39(1):87-93. doi: 10.4067/s0716-97602006000100010.
Copper is an essential and toxic trace metal for bacteria and, therefore, must be tightly regulated in the cell. Enterococcus hirae is a broadly studied model for copper homeostasis. The intracellular copper levels in E. hirae are regulated by the cop operon, which is formed by four genes: copA and copB that encode ATPases for influx and efflux of copper, respectively; copZ that encodes a copper chaperone; and copY, a copper responsive repressor. Since the complete genome sequence for E. hirae is not available, it is possible that other genes may encode proteins involved in copper homeostasis. Here, we identified a cop-like operon in nine species of Lactobacillale order with a known genome sequence. All of them always encoded a CopY-like repressor and a copper ATPase. The alignment of the cop-like operon promoter region revealed two CopY binding sites, one of which was conserved in all strains, and the second was only present in species of Streptococcus genus and L. johnsonii. Additional proteins associated to copper metabolism, CutC and Cupredoxin, also were detected. This study allowed for the description of the structure and organization of the cop operon and discussion of a phylogenetic hypothesis based on the differences observed in this operon's organization and its regulation in Lactobacillale order.
铜对于细菌而言既是必需的微量金属，又是有毒的微量金属，因此，细胞内的铜必须受到严格调控。海氏肠球菌是广泛研究的铜稳态模型。海氏肠球菌细胞内的铜水平由cop操纵子调控，该操纵子由四个基因组成：copA和copB，分别编码用于铜流入和流出的ATP酶；copZ，编码一种铜伴侣蛋白；以及copY，一种铜响应阻遏物。由于海氏肠球菌的完整基因组序列不可用，因此可能有其他基因编码参与铜稳态的蛋白质。在此，我们在九种已知基因组序列的乳杆菌目物种中鉴定出一个类cop操纵子。它们均编码一种类CopY阻遏物和一种铜ATP酶。类cop操纵子启动子区域的比对揭示了两个CopY结合位点，其中一个在所有菌株中都保守，另一个仅存在于链球菌属和约氏乳杆菌的物种中。还检测到了与铜代谢相关的其他蛋白质CutC和铜蓝蛋白。这项研究描述了cop操纵子的结构和组织，并基于在乳杆菌目中该操纵子的组织及其调控中观察到的差异，讨论了一种系统发育假说。
