Open AccessPseudomonas Quinolone Signal molecule PQS behaves like a B Class inhibitor at the I Q site of mitochondrial complex I
Author(s) -
Rieger Bettina,
Thierbach Sven,
Ommer Miriam,
Dienhart Finja S.V.,
Fetzner Susanne,
Busch Karin B.
Publication year - 2020
Publication title -
faseb bioadvances
Language(s) - English
Resource type - Journals
ISSN - 2573-9832
DOI - 10.1096/fba.2019-00084
Subject(s) - pseudomonas aeruginosa , coenzyme q – cytochrome c reductase , rotenone , pseudomonas , quinolone , chemistry , microbiology and biotechnology , biology , mitochondrion , biochemistry , antibiotics , bacteria , cytochrome c , genetics
Abstract Pseudomonas aeruginosa is a Gram‐negative bacterium of the proteobacteria class, and one of the most common causes of nosocomial infections. For example, it causes chronic pneumonia in cystic fibrosis patients. Patient sputum contains 2‐heptyl‐4‐hydroxyquinoline N ‐oxide [HQNO] and Pseudomonas quorum sensing molecules such as the Pseudomonas quinolone signal [PQS]. It is known that HQNO inhibits the enzyme activity of mitochondrial and bacterial complex III at the Q i (quinone reduction) site, but the target of PQS is not known. In this work we have shown that PQS has a negative effect on mitochondrial respiration in HeLa and A549 cells. It specifically inhibits the complex I of the respiratory chain. In vitro analyses showed a partially competitive inhibition with respect to ubiquinone at the I Q site. In competing studies with Rotenone, PQS suppressed the ROS‐promoting effect of Rotenone, which is typical for a B‐type inhibitor. Prolonged incubation with PQS also had an effect on the activity of complex III.