Molecular architecture of a eukaryotic translational initiation complex

Science. 2013 Nov 15;342(6160):1240585. doi: 10.1126/science.1240585. Epub 2013 Nov 7.

Abstract

The last step in eukaryotic translational initiation involves the joining of the large and small subunits of the ribosome, with initiator transfer RNA (Met-tRNA(i)(Met)) positioned over the start codon of messenger RNA in the P site. This step is catalyzed by initiation factor eIF5B. We used recent advances in cryo-electron microscopy (cryo-EM) to determine a structure of the eIF5B initiation complex to 6.6 angstrom resolution from <3% of the population, comprising just 5143 particles. The structure reveals conformational changes in eIF5B, initiator tRNA, and the ribosome that provide insights into the role of eIF5B in translational initiation. The relatively high resolution obtained from such a small fraction of a heterogeneous sample suggests a general approach for characterizing the structure of other dynamic or transient biological complexes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analytic Sample Preparation Methods
  • Cryoelectron Microscopy / methods
  • Eukaryotic Initiation Factors / chemistry*
  • Humans
  • Peptide Chain Initiation, Translational*
  • Protein Conformation
  • RNA, Transfer, Met / chemistry
  • Ribosomes / chemistry*
  • Saccharomyces cerevisiae

Substances

  • Eukaryotic Initiation Factors
  • RNA, Transfer, Met
  • eukaryotic initiation factor-5B

Associated data

  • PDB/4BYL
  • PDB/4BYN
  • PDB/4BYO
  • PDB/4BYP
  • PDB/4BYQ
  • PDB/4BYR
  • PDB/4BYS
  • PDB/4BYT
  • PDB/4BYU
  • PDB/4BYV
  • PDB/4BYW
  • PDB/4BYX