An essential GTPase that binds both GDP and GTP, with rapid nucleotide exchange. Plays a role in 16S rRNA processing and 30S ribosomal subunit biogenesis and possibly also in cell cycle regulation and energy metabolism (By similarity). Complements an E.coli era disruption mutant. Binds 16S rRNA as well as poly(U) RNA, binding to the latter is inhibited by liposomes. Monomer. The Era-type G (guanine nucleotide-binding) domain has GTPase activity, while the C-terminal KH type-2 domain is required for 16S rRNA binding and for membrane localization. Neither rRNA binding nor membrane localization require the N-terminal G domain, and the GTPase does not require the KH domain. It is estimated there is 0.63 ng Era per ug total cell protein in this strain. Belongs to the TRAFAC class TrmE-Era-EngA-EngB-Septin-like GTPase superfamily. Era GTPase family.