Reactive oxygen species target specific tryptophan site in the mitochondrial ATP synthase

Abstract

The release of reactive oxygen species (ROS) as side products of aerobic metabolism in the mitochondria is an unavoidable consequence. As the capacity of organisms to deal with this exposure declines with age, accumulation of molecular damage caused by ROS has been defined as one of the central events during the ageing process in biological systems as well as in numerous diseases such as Alzheimer's and Parkinson's Dementia. In the filamentous fungus Podospora anserina, an ageing model with a clear defined mitochondrial etiology of ageing, in addition to the mitochondrial aconitase the ATP synthase alpha subunit was defined recently as a hot spot for oxidative modifications induced by ROS. In this report we show, that this reactivity is not randomly distributed over the ATP Synthase, but is channeled to a single tryptophan residue 503. This residue serves as an intra-molecular quencher for oxidative species and might also be involved in the metabolic perception of oxidative stress or regulation of enzyme activity. A putative metal binding site in the proximity of this tryptophan residue appears to be crucial for the molecular mechanism for the selective targeting of oxidative damage.

Global Protein Oxidation Profiling Suggests Efficient Mitochondrial Proteome Homeostasis During Aging

“…The cultivation of the wild-type strain s and the isolation of crude mitochondrial fractions from P. anserina were performed as previously described (42). Cultures of six individuals serving as biological replicates were harvested at four different age stages (6 days, 9 days, 13 days and 16 days) resulting in a total of 24 mitochondrial samples.…”

“…The underlying reasons for the latter are probably both biological and technical. For instance, a previous determination of the oxidation degree in ATP synthase from P. anserina (42) suggests a low amount of oxidized species for many proteins. Moreover, the oxidized peptide is more hydrophilic than its corresponding nonmodified form, leading to differences in elution and consequently different interferences from co-eluting background ions during RP chromatography.…”

Functional Characterization of the Small Regulatory Subunit PetP from the Cytochrome b6f Complex in Thermosynechococcus elongatus

“…LC-MS analysis for protein identification was performed according to Rexroth et al (2012) with slight modifications. For reverse phase chromatography, a gradient of solvent A (95% water, 5% acetonitrile, and 0.1% formic acid) and solvent B (10% water, 85% acetonitrile, 5% isopropanol, and 0.1% formic acid) was used.…”

Analysis of protein profile of tomato root infected with Fusarium oxysporum f. sp lycopersici

“…ATP synthase is a key protein responsible for energy production (Rexroth et al, 2012). The ROS production, resulting from the infection, directly affects the efficiency of this enzyme due to oxidation of its tryptophan residues, resulting in degradation of the enzyme oxidized by specific proteases (Rexroth et al, 2012).…”

“…ATP synthase is a key protein responsible for energy production (Rexroth et al, 2012). The ROS production, resulting from the infection, directly affects the efficiency of this enzyme due to oxidation of its tryptophan residues, resulting in degradation of the enzyme oxidized by specific proteases (Rexroth et al, 2012). The decreased expression of proteins, such as malate dehydrogenase and triose phosphate isomerase, linked to energy cycles (Hadži-Tašković Šukalović et al, 2011), is related to resource reduction for the fungus and limits its development.…”