Unprecedented Properties of Phenothiazines Unraveled by a NDH-2 Bioelectrochemical Assay Platform.
J Am Chem Soc
; 142(3): 1311-1320, 2020 01 22.
Article
en En
| MEDLINE
| ID: mdl-31880924
ABSTRACT
Type II NADHquinone 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 antiprotozoal 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 antitubercular agent and key medicine used to treat psychotic disorders, is able to disrupt pH gradients across bacterial membranes.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Fenotiazinas
/
Técnicas Electroquímicas
Idioma:
En
Revista:
J Am Chem Soc
Año:
2020
Tipo del documento:
Article
País de afiliación:
Nueva Zelanda