Identification of new inhibitors for alternative NADH dehydrogenase (NDH-II).

In bacterial membranes and plant, fungus and protist mitochondria, NADH dehydrogenase (NDH-II) serves as an alternative NADH : quinone reductase, a non-proton-pumping single-subunit enzyme bound to the membrane surface. Because NDH-II is absent in mammalian mitochondria, it is a promising target for new antibiotics. However, inhibitors for NDH-II are rare and unspecific. Taking advantage of the simple organization of the respiratory chain in Gluconobacter oxydans, we carried out screening of natural compounds and identified scopafungin and gramicidin S as inhibitors for G. oxydans NDH-II. Further, we examined their effects on Mycobacterium smegmatis and Plasmodium yoelii NDH-II as model pathogen enzymes.