Methionine sulfoxide reductases protect Ffh from oxidative damages in Escherichia coli
Résumé
In proteins, methionine residues are primary targets for oxidation. Methionine oxidation is reversed by methionine sulfoxide reductases A and B, a class of highly conserved enzymes. Ffh protein, a component of the ubiquitous signal recognition particle, contains a methionine-rich domain, interacting with a small 4.5S RNA. In vitro analyses reported here show that: (i) oxidized Ffh is unable to bind 4.5S RNA, (ii) oxidized Ffh contains methionine sulfoxide residues, (iii) oxidized Ffh is a substrate for MsrA and MsrB enzymes; and (iv) MsrA/B repairing activities allow oxidized Ffh to recover 4.5S RNA-binding abilities. In vivo analyses reveal that: (i) Ffh synthesized in the msrA msrB mutant contains methionine sulfoxide residues and is unstable, (ii) msrA msrB mutant requires high levels of Ffh synthesis for growth and (iii) msrA msrB mutation leads to defects in Ffh-dependent targeting of MalF. We conclude that MsrA and MsrB are required to repair Ffh oxidized by reactive oxygen species produced by aerobic metabolism, establishing an as-yet undescribed link between protein targeting and oxidation.
Mots clés
methionine
methionine sulfoxide reductase
methionine sulfoxide reductase a
methionine sulfoxide reductase b
protein ffh
reactive oxygen metabolite
RNA
unclassified drug
aerobic metabolism
animal cell
article
controlled study
Escherichia coli
nonhuman
oxidation
priority journal
protein domain
protein RNA binding
protein synthesis
protein targeting
Amino Acid Sequence
Escherichia coli Proteins
Mass Spectrometry
Membrane Proteins
Molecular Sequence Data
Mutation
Oxidation-Reduction
Oxidative Stress
Oxidoreductases
Protein Binding
Protein Transport
Signal Recognition Particle
Substrate Specificity
Animalia
Negibacteria