Nakatani, Y, Shimaki, Y, Debajyoti, D et al. (4 more authors) (2020) Unprecedented mode of action of phenothiazines as ionophores unravelled by an NDH-2 bioelectrochemical assay platform. Journal of the American Chemical Society, 142 (3). pp. 1311-1320. ISSN 0002-7863
Abstract
Type II NADH:quinone oxidoreductase (NDH-2) plays a crucial role in the respiratory chains of many organisms. Its absence in mammalian cells makes NDH-2 an attractive new target for developing antimicrobials and anti-protozoal agents. We established a novel bioelectrochemical platform to characterize the catalytic behavior of NDH-2 from Caldalkalibacillus thermarum and Listeria monocytogenes strain EGD-e while bound to native-like lipid membranes. Catalysis of both NADH oxidation and lipophilic quinone reduction by membrane-bound NDH-2 followed the Michaelis–Menten model; however, the maximum turnover was only achieved when a high concentration of quinone (>3 mM) was present in the membrane, suggesting that quinone availability regulates NADH-coupled respiration activity. The quinone analogue 2-heptyl-4-hydroxyquinoline-N-oxide inhibited C. thermarum NDH-2 activity and its potency is higher in a membrane environment compared to assays performed with water-soluble quinone analogues, demonstrating the importance of testing compounds under physiologically relevant conditions. Furthermore, when phenothiazines, one of the most commonly identified NDH-2 inhibitors, were tested, they did not inhibit membrane-bound NDH-2. Instead, our assay platform unexpectedly suggests a novel mode of phenothiazine action where chlorpromazine, a promising anti-tubercular agent and key medicine used to treat psychotic disorders, is able to disrupt pH gradients across bacterial membranes.
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Copyright, Publisher and Additional Information: | © 2019 American Chemical Society. This is an author produced version of a paper published in Journal of the American Chemical Society. Uploaded in accordance with the publisher's self-archiving policy. | ||||||
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Institution: | The University of Leeds | ||||||
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Biomedical Sciences (Leeds) | ||||||
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Depositing User: | Symplectic Publications | ||||||
Date Deposited: | 02 Jan 2020 12:23 | ||||||
Last Modified: | 27 Dec 2020 01:38 | ||||||
Status: | Published | ||||||
Publisher: | American Chemical Society | ||||||
Identification Number: | https://doi.org/10.1021/jacs.9b10254 |