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Biochim Biophys Acta Bioenerg. 2018 Feb;1859(2):110-118. doi: 10.1016/j.bbabio.2017.10.006. Epub 2017 Oct 28.

Cytochromes bd-I and bo3 are essential for the bactericidal effect of microcin J25 on Escherichia coli cells.

Author information

1
Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT) and Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Chacabuco 461, T4000ILI San Miguel de Tucumán, Argentina.
2
Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA.
3
Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT) and Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Chacabuco 461, T4000ILI San Miguel de Tucumán, Argentina. Electronic address: augustobellomio@fbqf.unt.edu.ar.

Abstract

Microcin J25 has two targets in sensitive bacteria, the RNA polymerase, and the respiratory chain through inhibition of cellular respiration. In this work, the effect of microcin J25 in E. coli mutants that lack the terminal oxidases cytochrome bd-I and cytochrome bo3 was analyzed. The mutant strains lacking cytochrome bo3 or cytochrome bd-I were less sensitive to the peptide. In membranes obtained from the strain that only expresses cytochrome bd-I a great ROS overproduction was observed in the presence of microcin J25. Nevertheless, the oxygen consumption was less inhibited in this strain, probably because the oxygen is partially reduced to superoxide. There was no overproduction of ROS in membranes isolated from the mutant strain that only express cytochrome bo3 and the inhibition of the cellular respiration was similar to the wild type. It is concluded that both cytochromes bd-I and bo3 are affected by the peptide. The results establish for the first time a relationship between the terminal oxygen reductases and the mechanism of action of microcin J25.

KEYWORDS:

Cytochrome; MICROCIN J25; ROS; Respiratory chain

PMID:
29107655
DOI:
10.1016/j.bbabio.2017.10.006
[Indexed for MEDLINE]
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