Periplasmic proteins encoded by VCA0261-0260 and VC2216 genes together with copA and cueR products are required for copper tolerance but not for virulence in Vibrio cholerae.
The bacterial pathogen Vibrio cholerae requires colonizination of the human small intestine to cause cholera. The anaerobic and slightly acidic conditions predominating there enhance toxicity of low copper concentrations and create a selective environment for bacteria with evolved detoxifying mechanisms. We reported previously that the VCA0260, VCA0261 and VC2216 gene products were synthesized only in V. cholerae grown in microaerobiosis or anaerobiosis. Here we show that ORFs VCA0261 and VCA0260 are actually combined into a single gene encoding a 18.7 kDa protein. Bioinformatic analyses linked this protein and the VC2216 gene product to copper tolerance. Following the approach of predict-mutate and test, we describe for the first time, to our knowledge, the copper tolerance systems operating in V. cholerae. Copper susceptibility analyses of mutants in VCA0261-0260, VC2216 or in the putative copper-tolerance-related VC2215 (copA ATPase) and VC0974 (cueR), under aerobic and anaerobic growth, revealed that CopA represents the main tolerance system under both conditions. The VC2216-encoded periplasmic protein contributes to resistance only under anaerobiosis in a CopA-functional background. The locus tag VCA0261-0260 encodes a copper-inducible, CueR-dependent, periplasmic protein, which mediates tolerance in aerobiosis, but under anaerobiosis its role is only evident in CopA knock-out mutants. None of the genes involved in copper homeostasis were required for V. cholerae virulence or colonization in the mouse model. We conclude that copper tolerance in V. cholerae, which lacks orthologues of the periplasmic copper tolerance proteins CueO, CusCFBA and CueP, involves CopA and CueR proteins along with the periplasmic Cot (VCA0261-0260) and CopG (VC2216) V. cholerae homologues.
Department of Molecular Biology, National Centre for Scientific Research, PO Box 6412, Havana, Cuba.
Karen
K
Marrero
Department of Proteomics, Centre for Genetic Engineering and Biotechnology, PO Box 6162, Havana, Cuba.
Aniel
A
Sánchez
Department of Proteomics, Centre for Genetic Engineering and Biotechnology, PO Box 6162, Havana, Cuba.
Luis Javier
LJ
González
Department of Molecular Biology, National Centre for Scientific Research, PO Box 6412, Havana, Cuba.
Talena
T
Ledón
Department of Bioinformatics, Centre for Genetic Engineering and Biotechnology, PO Box 6162, Havana, Cuba.
Arielis
A
Rodríguez-Ulloa
Department of Proteomics, Centre for Genetic Engineering and Biotechnology, PO Box 6162, Havana, Cuba.
Lila
L
Castellanos-Serra
Department of Molecular Biology, National Centre for Scientific Research, PO Box 6412, Havana, Cuba.
Celso
C
Pérez
Department of Molecular Biology, National Centre for Scientific Research, PO Box 6412, Havana, Cuba.
Rafael
R
Fando
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002771:Cholera / Q000382:microbiology*; D003300:Copper / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D033903:Periplasmic Proteins / Q000235:genetics / Q000378:metabolism*; D014734:Vibrio cholerae / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D014774:Virulence
D001426:Bacterial Proteins; D033903:Periplasmic Proteins; D003300:Copper