Initiation factor 2 crystal structure reveals a different domain organization from eukaryotic initiation factor 5B and mechanism among translational GTPases

Daniel Eiler , Jinzhong Lin , Angelita Simonetti (1) , Bruno Klaholz (1) , Thomas Steitz

1 IGBMC - Institut de Génétique et de Biologie Moléculaire et Cellulaire

Significance Initiation factor 2 (IF2) is a GTPase that functions within the 30S ribosomal initiation complex and promotes its joining with the 50S ribosomal subunit to form a 70S ribosome. The role of IF2 in translation initiation is not well understood. We present an atomic resolution crystal structure of the full-length IF2, and we are able to explain why prokaryotes and eukaryotes have similar proteins with different mechanisms to guide ribosome assembly. We provide a structural explanation for why the mechanism of IF2 is unique among translational GTPases and acts more as a novel conformational switch.

Domaines: Biochimie, Biologie Moléculaire

Daniel Eiler, Jinzhong Lin, Angelita Simonetti, Bruno Klaholz, Thomas Steitz. Initiation factor 2 crystal structure reveals a different domain organization from eukaryotic initiation factor 5B and mechanism among translational GTPases. Proceedings of the National Academy of Sciences of the United States of America, 2013, 110 (39), pp.15662-15667. ⟨10.1073/pnas.1309360110⟩. ⟨hal-04414035⟩