Format

Send to

Choose Destination
Sci Adv. 2016 Mar 4;2(3):e1501502. doi: 10.1126/sciadv.1501502. eCollection 2016 Mar.

Structures of ribosome-bound initiation factor 2 reveal the mechanism of subunit association.

Author information

1
Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
2
Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.; UltraStrukturNetzwerk, Max Planck Institute for Molecular Genetics, Ihnestrasse 73, 14195 Berlin, Germany.

Abstract

Throughout the four phases of protein biosynthesis-initiation, elongation, termination, and recycling-the ribosome is controlled and regulated by at least one specified translational guanosine triphosphatase (trGTPase). Although the structural basis for trGTPase interaction with the ribosome has been solved for the last three steps of translation, the high-resolution structure for the key initiation trGTPase, initiation factor 2 (IF2), complexed with the ribosome, remains elusive. We determine the structure of IF2 complexed with a nonhydrolyzable guanosine triphosphate analog and initiator fMet-tRNAi (Met) in the context of the Escherichia coli ribosome to 3.7-Å resolution using cryo-electron microscopy. The structural analysis reveals previously unseen intrinsic conformational modes of the 70S initiation complex, establishing the mutual interplay of IF2 and initator transfer RNA (tRNA) with the ribsosome and providing the structural foundation for a mechanistic understanding of the final steps of translation initiation.

KEYWORDS:

protein biosynthesis; structural biology; translational guanosine triphosphatase (trGTPase)

PMID:
26973877
PMCID:
PMC4783127
DOI:
10.1126/sciadv.1501502
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for PubMed Central
Loading ...
Support Center