Research Article

Crystal Structure of the Eukaryotic 40S Ribosomal Subunit in Complex with Initiation Factor 1

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Science  23 Dec 2010:
1198308
DOI: 10.1126/science.1198308

Abstract

Eukaryotic ribosomes are substantially larger and more complex than their bacterial counterparts. Although their core function is conserved, bacterial and eukaryotic protein synthesis differ considerably at the level of initiation. The eukaryotic small ribosomal subunit (40S) plays a central role in this process; it binds initiation factors that facilitate scanning of messenger RNAs and initiation of protein synthesis. We have determined the crystal structure of the Tetrahymena thermophila 40S ribosomal subunit in complex with eukaryotic initiation factor 1 (eIF1) at 3.9 Å resolution. The structure reveals the fold of the entire 18S rRNA and of all ribosomal proteins of the 40S subunit and defines the interactions with the eIF1. It provides insights into the eukaryotic-specific aspects of protein synthesis including the function of eIF1, and signaling and regulation mediated by ribosomal proteins RACK1 and rpS6e.