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). The Era binding site on the 30S subunit overlaps that of protein S1 and is in direct contact with 5 nucleotides directly upstream of the anti-Shine-Dalgarno sequence; the presence of Era may prevent mRNA recruitment. 30S subunits bound to Era are not able to bind to the 50S subunit to make functional ribosomes. Era may serve a role in the final stages of 30S ribosomal subunit assembly. Monomer (Probable). Binds to the 30S ribosomal subunit, between the head and platform, contacting the 16S rRNA. Contacts ribosomal proteins S7 and S18 and may contact proteins S2 and S11. Belongs to the TRAFAC class TrmE-Era-EngA-EngB-Septin-like GTPase superfamily. Era GTPase family.