Molecular Architecture of a Eukaryotic Translational Initiation Complex

Overview

Journal Science

Specialty Science

Date 2013 Nov 9

PMID 24200810

Citations 81

Authors

Israel S Fernandez

Xiao-Chen Bai

Tanweer Hussain

Ann C Kelley

Jon R Lorsch

V Ramakrishnan

Sjors H W Scheres

Affiliations

Soon will be listed here.

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.

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