Expression of multiple <i>cbb</i><sub>3</sub> cytochrome <i>c</i> oxidase isoforms by combinations of multiple isosubunits in <i>Pseudomonas aeruginosa</i>.
basic_science · Level V
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- Record sourced from PubMed, PMID 27791152.
- Also identified by DOI 10.1073/pnas.1613308113 and PMC identifier 5111723.
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Abstract
The ubiquitous opportunistic human pathogen <i>Pseudomonas aeruginosa</i> has five terminal oxidases for aerobic respiration and uses them under different growth conditions. Two of them are <i>cbb</i><sub>3</sub>-type cytochrome <i>c</i> oxidases encoded by the gene clusters <i>ccoN1O1Q1P1</i> and <i>ccoN2O2Q2P2</i>, which are the main terminal oxidases under high- and low-oxygen conditions, respectively. <i>P. aeruginosa</i> also has two orphan gene clusters, <i>ccoN3Q3</i> and <i>ccoN4Q4</i>, encoding the core catalytic CcoN isosubunits, but the roles of these genes have not been clarified. We found that 16 active <i>cbb</i><sub>3</sub> isoforms could be produced by combinations of four CcoN, two CcoO, and two CcoP isosubunits. The CcoN3- or CcoN4-containing isoforms were produced in the WT cell membrane in response to nitrite and cyanide, respectively. The strains carrying these isoforms were more resistant to nitrite or cyanide under low-oxygen conditions. These results indicate that <i>P. aeruginosa</i> gains resistance to respiratory inhibitors using multiple <i>cbb</i><sub>3</sub> isoforms with different features, which are produced through exchanges of multiple core catalytic isosubunits.