Haixiao Gao*, Zhihong Zhou*, Urmila Rawat, Chenhui Huang , Lamine Bouakaz, Chernhoe Wang, Zhihong Cheng, Yuying Liu, Andrey Zavialov, Richard Gursky, Suparna Sanyal, Måns Ehrenberg, Joachim Frank, and Haiwei Song
* These authors contributed equally to this work.
During translation termination, class-II release factor RF3 binds to the ribosome to promote rapid dissociation of a class-I release factor (RF) in a GTP-dependent manner. We present the crystal structure of E. coli RF3•GDP, which has a three-domain architecture strikingly similar to the structure of EF-Tu•GTP. Biochemical data on RF3 mutants show that a surface region involving domains II and III is important for distinct steps in the action cycle of RF3. Furthermore, we present a cryo-electron microscopy (cryo-EM) structure of the post-termination ribosome bound with RF3 in the GTP form. Our data show that RF3•GTP binding induces large conformational changes in the ribosome, which break the interactions of the class-I RF with both the decoding center and the GTPase-associated center of the ribosome, apparently leading to the release of the class-I RF.
Published in Cell online DOI 10.10.1016/j.cell.2007.03.050 on June 1, 2007