Characterization of the type 2 NADH:menaquinone oxidoreductases from Staphylococcus aureus and the bactericidal action of phenothiazines.
Methicillin-resistant Staphylococcus aureus (MRSA) is currently one of the principal multiple drug resistant bacterial pathogens causing serious infections, many of which are life-threatening. Consequently, new therapeutic targets are required to combat such infections. In the current work, we explore the type 2 Nicotinamide adenine dinucleotide reduced form (NADH) dehydrogenases (NDH-2s) as possible drug targets and look at the effects of phenothiazines, known to inhibit NDH-2 from Mycobacterium tuberculosis. NDH-2s are monotopic membrane proteins that catalyze the transfer of electrons from NADH via flavin adenine dinucleotide (FAD) to the quinone pool. They are required for maintaining the NADH/Nicotinamide adenine dinucleotide (NAD(+)) redox balance and contribute indirectly to the generation of proton motive force. NDH-2s are not present in mammals, but are the only form of respiratory NADH dehydrogenase in several pathogens, including S. aureus. In this work, the two putative ndh genes present in the S. aureus genome were identified, cloned and expressed, and the proteins were purified and characterized. Phenothiazines were shown to inhibit both of the S. aureus NDH-2s with half maximal inhibitory concentration (IC50) values as low as 8μM. However, evaluating the effects of phenothiazines on whole cells of S. aureus was complicated by the fact that they are also acting as uncouplers of oxidative phosphorylation. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference.
Department of Biochemistry, University of Illinois, 600 S. Mathews Street, Urbana, IL 61801, USA.
Lici A
LA
Schurig-Briccio
Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Takahiro
T
Yano
Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Harvey
H
Rubin
Department of Biochemistry, University of Illinois, 600 S. Mathews Street, Urbana, IL 61801, USA. Electronic address: r-gennis@illinois.edu.
Robert B
RB
Gennis
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D020128:Inhibitory Concentration 50; D009245:NADH Dehydrogenase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D010640:Phenothiazines / Q000494:pharmacology*; D011808:Quinone Reductases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D013211:Staphylococcus aureus / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D010640:Phenothiazines; D011808:Quinone Reductases; D009245:NADH Dehydrogenase; C031637:phenothiazine
Bioenergetics/electron transfer complex; Enzyme inhibitor; NADH dehydrogenase; Phenothiazine; Respiratory chain; Staphylococcus aureus