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). Binds both GDP and GTP. Complements an E.coli era disruption mutant. Monomer. Constitutively expressed, two-fold induced at the end of the exponential phase; this is under control of Spo0A, suggesting it may have a role in sporulation. Essential in some but not all strains; in 168 / BR151 the null mutation grows slowly and forms irregularly shaped colonies after several days. In liquid culture forms chains of elongated cells with diffuse nucleoids that occupy most of the cell. Sporulation in this disruption strain is severely impaired. Essential in strains CRK6000 and IS75, where it cannot be disrupted. In CRK600 in depletion experiments cells become 1.5 to 2-fold longer and nucleoid distribution is dispersed. The number of replication origins increases, suggesting an increase in chromosome replication. Estimated to be present at 3000 copies per cell. Belongs to the TRAFAC class TrmE-Era-EngA-EngB-Septin-like GTPase superfamily. Era GTPase family.