Table.

Factors and mechanisms of stalled ribosome rescue

Cause of stalling	Rescue factor	Mechanism of ribosome rescue	Occurrence
Formation of stalled complexes	Trans-translation (tmRNA/SmpB)	Resumption of translation using tmRNA. Tagging of a polypeptide and mRNA	99% of bacterial genomes
	ArfA	RF2 factor recruitment	Gram-negative
	BrfA	RF2 factor recruitment	Bacullus subtilis
	ArfT	Recruitment of RF or RF2	Francisella tularensis
	ArfB	Independent hydrolysis of peptidyl-tRNA	Gram-negative and gram-positive
	HflX	Disassembly of ribosomal subunits	Gram-negative and gram-positive
Abrupt dissociation of subunits	RqcH/RqcP + ArfB (?)	Mimicking of translation elongation for attaching an Ala tag to a polypeptide. Hydrolysis	Except for gamma-proteobacteria and actinobacteria
	Hsp15 +ArfB(?)	Transfer of peptidyl-tRNA to the P-site. Hydrolysis	Gram-negative and gram-positive
Rare codon cluster, polyproline sequence, secondary structure	EF-P	Assistance in peptide bond formation in passing a difficult segment	Gram-negative and gram-positive
	EF-4	Assistance in passing a difficult segment	Gram-negative and gram-positive
	ArfB	Hydrolysis of peptidyl-tRNA	Gram-negative and gram-positive
Action of antibiotics	HflXr	Disassembly of ribosome	Listeria monocytogenes
	ABC-F-proteins	Antibiotic dissociation	Gram-positive
	PrfH-?	Unknown	Gram-negative and gram-positive