National Center for
3UOQ: Crystal Structure Of Release Factor Rf3 Trapped In The Gtp State On A Rotated Conformation Of The Ribosome (Without Viomycin)
Crystal structure of release factor RF3 trapped in the GTP state on a rotated conformation of the ribosome
RNA (2012) 18 p.230-240
The class II release factor RF3 is a GTPase related to elongation factor EF-G, which catalyzes release of class I release factors RF1 and RF2 from the ribosome after termination of protein synthesis. The 3.3 A crystal structure of the RF3.GDPNP.ribosome complex provides a high-resolution description of interactions and structural rearrangements that occur when binding of this translational GTPase induces large-scale rotational movements in the ribosome. RF3 induces a 7 degrees rotation of the body and 14 degrees rotation of the head of the 30S ribosomal subunit, and itself undergoes inter- and intradomain conformational rearrangements. We suggest that ordering of critical elements of switch loop I and the P loop, which help to form the GTPase catalytic site, are caused by interactions between the G domain of RF3 and the sarcin-ricin loop of 23S rRNA. The rotational movements in the ribosome induced by RF3, and its distinctly different binding orientation to the sarcin-ricin loop of 23S rRNA, raise interesting implications for the mechanism of action of EF-G in translocation.