GO_REF:0000002

Gene Ontology annotation through association of InterPro records with GO terms.

Automated source annotation reviewed against UniProt and literature evidence for this gene.

PMID:25686373

Arginine-rhamnosylation as new strategy to activate translation elongation factor P.

Primary discovery paper establishing EarP as the EF-P arginine rhamnosyltransferase; earP deletion phenocopies efp deletion (slow growth, ~10-fold reduced polyproline-LacZ reporter translation), providing the IMP evidence for EarP's role in translational elongation.

"providing clear experimental evidence that EarP is required for EF-P activity"
EarP rhamnosylates the conserved Arg32 of EF-P using dTDP-L-rhamnose, the first reported N-linked arginine glycosylation in bacteria and the first glycosylated EF-P side chain essential for function.

"EarP is an EF-P arginine rhamnosyltransferase essential for post-translational activation"

PMID:28951478

Structural Basis for EarP-Mediated Arginine Glycosylation of Translation Elongation Factor EF-P.

Structural and biochemical work characterized P. putida EarP-mediated arginine rhamnosylation of EF-P; in vivo PcadBA::lacZ reporter assays in E. coli Delta-efp show catalytically dead EarP variants phenocopy efp deletion, corroborating EarP's role in EF-P-dependent translation.

file:PSEPK/earP/earP-uniprot.txt

UniProtKB reviewed entry for earP

UniProt identifies earP function, pathway placement, catalytic activity, and/or localization used to review GOA annotations.

file:PSEPK/earP/earP-deep-research-falcon.md

Falcon (Edison Scientific) deep research report on earP (Q88LS1, PP_1857) in Pseudomonas putida KT2440

Falcon corroborates EarP as a cytosolic protein-arginine rhamnosyltransferase that activates EF-P, confirming the molecular function and biological role used in this review.

"encodes **EarP**, a cytosolic **protein-arginine rhamnosyltransferase**"
EarP catalyzes protein N-glycosylation on the EF-P Arg32 guanidino group using dTDP-L-rhamnose as donor.

"EarP performs **protein N-glycosylation on arginine**, specifically transferring a rhamnose to the **guanidino group** of EF-P **Arg32**."
EarP is an inverting glycosyltransferase that uses dTDP-L-rhamnose as its sugar donor.

"EarP uses **dTDP-L-rhamnose** as its sugar donor."
The biological consequence of EarP modification is EF-P-dependent rescue of polyproline-stalled ribosomes during translation elongation.

"Rhamnosylated EF-P is recruited to stalled ribosomes and promotes peptide-bond formation, especially at problematic **polyproline motifs**"
EarP recognizes the KOW-like N-terminal domain of EF-P and modifies the conserved Arg32; donor binding occurs in a conserved C-domain pocket of a GT-B fold.

"EarP recognizes the **KOW-like N-terminal domain** of EF-P"
EarP function is best supported as cytosolic, acting on soluble EF-P; no evidence supports secretion or membrane localization.

"based on substrate identity (soluble EF-P) and functional models placing activated EF-P on cytosolic ribosomes"