Alternative ribosome-rescue factor A

Rescues ribosomes stalled at the 3' end of non-stop mRNAs (PubMed:21062370, PubMed:21435036). This activity is crucial when the stalled ribosome cannot be rescued by the SsrA(tmRNA)-SmpB quality control system (PubMed:21062370, PubMed:21435036). Binds the 30S subunit, contacting 16S rRNA with the N-terminus near the decoding center and its C-terminus in the mRNA entry channel; contacts change in the presence of release factor 2 (RF2, also named PrfB) (PubMed:25355516, PubMed:27906160, PubMed:27906161, PubMed:27934701, PubMed:28077875). Requires RF2/PrfB to hydrolyze stalled peptidyl-tRNA on the ribosome; recruits and probably helps position RF2/PrfB correctly in the ribosomal A site so RF2's GGQ motif can hydrolyze the peptidyl-tRNA bond (PubMed:22857598, PubMed:22922063, PubMed:25355516, PubMed:27906160, PubMed:27906161, PubMed:27934701, PubMed:28077875). Does not release ribosomes with a programmed pause caused by regulatory chains such as SecM-mediated pausing (PubMed:22857598). Binds tRNA which may stimulate its ribosome rescue activity (PubMed:22857598).