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Abstract:
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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. |