Dissertations, Theses, and Capstone Projects

Date of Degree

2-2025

Document Type

Dissertation

Degree Name

Ph.D.

Program

Biochemistry

Advisor

Amédée des Georges

Committee Members

Kevin Gardner

Dixie Goss

Anuradha Janakiraman

John Hunt

Subject Categories

Biochemistry, Biophysics, and Structural Biology

Keywords

Cryo-EM, translation, eIF2D

Abstract

eIF2D (65kDa) is a protein highly conserved in eukaryotic organisms. eIF2D has been implicated in non-canonical initiation. eIF2D was found to recruit initiator tRNA to the start codon of HCV-like Internal Ribosome Entry Sites (IRES) messenger RNAs (mRNAs) independently of other canonical factors. To shed light on the mechanism of eIF2D, we used cryo-transmission electron microscopy (cryo-EM) single particle analysis on the Classical Swine Fever Virus (ΔII CSFV) IRES•40S•eIF2D•Met-tRNAiMet initiation complex.

Single-particle cryo-EM reconstructions revealed that eIF2D stabilizes tRNA in the A site of the IRES-bound 40S subunit through its SWIB/MDM2-SUI and WH domains, which are absent in its homolog, MCT-1/DENR. The presence of an A-site tRNA induces a closed conformation, providing insights into how eIF2D coordinates non-canonical translation initiation. These findings enhance our understanding of eIF2D's unique structural mechanism.

Download

This work is embargoed and will be available for download on Monday, February 01, 2027

Share

COinS