Carbonylated proteins are detectable only in a degradation-resistant aggregate state in Escherichia coli.
Carbonylation is currently used as a marker for irreversible protein oxidative damage. Several studies indicate that carbonylated proteins are more prone to degradation than their nonoxidized counterparts. In this study, we observed that in Escherichia coli, more than 95% of the total carbonyl content consisted of insoluble protein and most were cytosolic proteins. We thereby demonstrate that, in vivo, carbonylated proteins are detectable mainly in an aggregate state. Finally, we show that detectable carbonylated proteins are not degraded in vivo. Here we propose that some carbonylated proteins escape degradation in vivo by forming carbonylated protein aggregates and thus becoming nondegradable. In light of these findings, we provide evidence that the accumulation of nondegradable carbonylated protein presented in an aggregate state contributes to the increases in carbonyl content observed during senescence.
Maisonneuve
Etienne
E
Laboratoire de Chimie Bactérienne, Université de la Méditerranée, UPR 9043-CNRS, 31, Chemin Joseph Aiguier, 13402 Marseille, France.
Fraysse
Laetitia
L
Lignon
Sabrina
S
Capron
Laure
L
Dukan
Sam
S
D002853:Chromatography, Liquid; D003593:Cytoplasm / Q000737:chemistry; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D050050:Protein Carbonylation; D012995:Solubility; D053719:Tandem Mass Spectrometry
D029968:Escherichia coli Proteins