RNA recognition motif (RRM) found in Escherichia coli RNA helicase dbpA and similar proteins
This subgroup corresponds to the C-terminal RRM homology domain of dbpA. E. coli dbpA is a member of the DbpA subfamily of prokaryotic DEAD-box rRNA helicases that have been implicated in ribosome biogenesis. It binds with high affinity and specificity for RNA substrates containing hairpin 92 of 23S rRNA (HP92) with either 3' or 5' extensions. As a non-processive ATP-dependent helicase, DbpA destabilizes and unwinds short <9bp (base pairs) RNA duplexes as well as long duplex RNA stretches. It disrupts RNA helices exclusively in a 3'- 5' direction and requires a single-stranded loading site 3' of the substrate helix. dbpA contains two N-terminal ATPase catalytic domains and a C-terminal RNA binding domain, an atypical RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNPs (ribonucleoprotein domain). The catalytic domains bind to nearby regions of RNA to stimulate ATP hydrolysis and disrupt RNA structures. The C-terminal domain binds specifically to hairpin 92.