E. coli 4.5S RNA is part of a ribonucleoprotein particle that has properties related to signal recognition particle

The signal recognition particle receptor of Escherichia coli (FtsY) has a nucleotide exchange factor built into the GTPase domain

“…The process is regulated by GTPases present as distinct domains (G domains) in the SRP and its receptor. In Escherichia coli, the SRP consists of only one protein, the Ffh ( fifty four homologue, P48, or SRP54 homologue) and a 4.5S RNA (3,4). The protein FtsY has been identified as the functional homologue of the eukaryotic SRP receptor SR␣ (5).…”

Sec-dependent protein export and the involvement of the molecular chaperone SecB

“…In vitro, both E coli Ffh and SRP54 specifically bind to 4.5S RNA. These results suggest that 4.5S RNA can functionally be replaced by 7S RNA from human SRP (Ribes et al 1990). When E coli cells are depleted of 4.5S RNA, the translocation of Bla is strongly impaired but that of MBP, ribose-binding protein (RBP), and OmpA are unaffected (Poritz et al 1990;Ribes et al 1990).…”

Hybridization of two oligodeoxynucleotides to both strands of an RNA hairpin structure increases the efficiency of RNA‐DNA duplex formation

“…Especially, secondary structures of apical domains are similar, even between bacteria and mammals [9,10], implicating common functional features. Secondly, 4.5S RNA supports protein synthesis [11,12] and forms together with the protein Ffh the SRP of E. cob [13]. Studies on the secondary structure of the apical domain will provide further information on the function of bacterial SRP as did mutation experiments [14].…”