XStructure of the mammalian ribosomal 43S preinitiation complex bound to the scanning factor DHX29

Yaser Hashem, Amedee Des Georges, Vidya Dhote, Robert Langlois, Hstau Y. Liao, Robert A. Grassucci, Christopher U.T. Hellen, Tatyana V. Pestova, Joachim Frank

Research output: Contribution to journalArticlepeer-review


Eukaryotic translation initiation begins with assembly of a 43S preinitiation complex. First, methionylated initiator methionine transfer RNA (Met-tRNAiMet), eukaryotic initiation factor (eIF) 2, and guanosine triphosphate form a ternary complex (TC). The TC, eIF3, eIF1, and eIF1A cooperatively bind to the 40S subunit, yielding the 43S preinitiation complex, which is ready to attach to messenger RNA (mRNA) and start scanning to the initiation codon. Scanning on structured mRNAs additionally requires DHX29, a DExH-box protein that also binds directly to the 40S subunit. Here, we present a cryo-electron microscopy structure of the mammalian DHX29-bound 43S complex at 11.6 Å resolution. It reveals that eIF2 interacts with the 40S subunit via its α subunit and supports Met-tRNAiMet in an unexpected P/I orientation (eP/I). The structural core of eIF3 resides on the back of the 40S subunit, establishing two principal points of contact, whereas DHX29 binds around helix 16. The structure provides insights into eukaryote-specific aspects of translation, including the mechanism of action of DHX29.

Original languageEnglish (US)
Pages (from-to)1108
Number of pages1
Issue number5
StatePublished - May 23 2013

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology


Dive into the research topics of 'XStructure of the mammalian ribosomal 43S preinitiation complex bound to the scanning factor DHX29'. Together they form a unique fingerprint.

Cite this