Distinct functions of elongation factor G in ribosome recycling and translocation

Single-round GTP hydrolysis by EF-G in the absence and presence of RRF. Post-termination complex (Materials and Methods; 1 μM final concentration after mixing) was rapidly mixed with IF3 (2 μM), [γ-³²P]GTP (30 μM), and EF-G (3 μM) alone (●) or together with RRF (5 μM) (○). The extent of GTP hydrolysis is presented relative to the input of post-termination complex. Single-exponential fitting yielded a rate of GTP hydrolysis of 75 ± 25 sec⁻¹ (4°C).