Anti-ETFB (aa 152-165) polyclonal antibody

Eubacterium limosum KIST612 is one of the few acetogens that can produce butyrate from carbon monoxide. We have used a genome-guided analysis to delineate the path of butyrate formation, the enzymes involved, and the potential coupling to ATP synthesis. Oxidation of CO is catalyzed by the acetyl-coenzyme A (CoA) synthase/CO dehydrogenase and coupled to the reduction of ferredoxin. Oxidation of reduced ferredoxin is catalyzed by the Rnf complex and Na+ dependent. Consistent with the finding of a Na+-dependent Rnf complex is the presence of a conserved Na+-binding motif in the c subunit of the ATP synthase. Butyrate formation is from acetyl-CoA via acetoacetyl-CoA, hydroxybutyryl-CoA, crotonyl-CoA, and butyryl-CoA and is consistent with the finding of a gene cluster that encodes the enzymes for this pathway. The activity of the butyryl-CoA dehydrogenase was demonstrated. Reduction of crotonyl-CoA to butyryl-CoA with NADH as the reductant was coupled to reduction of ferredoxin. We postulate that the butyryl-CoA dehydrogenase uses flavin-based electron bifurcation to reduce ferredoxin, which is consistent with the finding of etfA and etfB genes next to it. The overall ATP yield was calculated and is significantly higher than the one obtained with H-2 + CO2. The energetic benefit may be one reason that butyrate is formed only from CO but not from H-2 + CO2.

Electron-transferring flavoprotein (ETF) and its dehydrogenase (ETFDH) are highly conserved electron carriers which mainly function in mitochondrial fatty acid beta oxidation. Here, we report the identification and characterization of ETF alpha and beta subunit encoding genes (ETFA and ETFB) and ETFDH encoding gene (ETFDH) in the rice blast fungus Magnaporthe oryzae. It was demonstrated that, by impacting fatty acid metabolism, ETF and ETFDH mutations led to severe growth and conidiation defects, which could be largely rescued by exogenous acetate or carbonate. Furthermore, although conidium germination and appressorium formation appeared to be normal in ETF and ETFDH mutants, most appressoria failed to penetrate the host epidermis due to low turgor pressure. The few appressoria that succeeded in penetration were severely restricted in invasive growth and consequently failed to cause disease. Moreover, ETF mutant etfb(-) induced ROS accumulation in infected host cells and exogenous antioxidant GSH accelerated mutant invading growth without increasing the penetration rate. In addition, mutant etfb(-) displayed elevated lipid body accumulation and reduced ATP synthesis. Taken together, ETF and ETFDH play an important role in fungal development and plant infection in M. oryzae by regulation of fatty acid metabolism, turgor establishment and induction of host ROS accumulation.