a 2025

STEPWISE MECHANISM OF IF2 α-DRIVEN BACTERIAL TRANSLATION INITIATION

SOARES GUERRA, Gabriel; Hassan ZAFAR; XUELIANG GE; Ahmed Adel Ibrahim Hassona HASSAN; Sylva BRABENCOVÁ et. al.

Basic information

Original name

STEPWISE MECHANISM OF IF2 α-DRIVEN BACTERIAL TRANSLATION INITIATION

Authors

SOARES GUERRA, Gabriel; Hassan ZAFAR; XUELIANG GE; Ahmed Adel Ibrahim Hassona HASSAN; Sylva BRABENCOVÁ; Lucie SLÁMOVÁ; HOWARD GAMPER; HOU YA-MING; SUPARNA SANYAL and Gabriel DEMO

Edition

4th Annual Meeting of the National Institute of Virology and Bacteriology (NIVB), Kutná Hora, 2025

Other information

Language

English

Type of outcome

Konferenční abstrakta

Country of publisher

Czech Republic

Confidentiality degree

is not subject to a state or trade secret

References:

URL

Organization

Středoevropský technologický institut – Repository – Repository

ISSN

Keywords in English

translation initiation; IF2 α-isoform; time-resolved cryo-EM; IF2 α–mediated initiation

Links

LX22NPO5103, research and development project.
Changed: 2/12/2025 00:51, RNDr. Daniel Jakubík

Abstract

In the original language

Bacterial translation initiation is a key regulatory step in gene expression, requiring precise coordination between initiator tRNA recruitment, initiation factors, and ribosomal subunit joining. The process begins with the placement of the initiator tRNA fMet into the P-site of the 30S subunit, aided by initiation factor 1 (IF1) in the A-site and initiation factor 2 (IF2), a GTPase, promoting 50S subunit docking to form the 70S initiation complex (IC). IF2 exists in three isoforms ( α, β, γ) in E. coli , with the αα-form being the most active in promoting initiation. Despite its functional importance, the α-form has never been structurally and mechanistically characterised in the context of the complete initiation pathway. In particular, the influence of its extended N-terminal domain on subunit joining and the molecular sequence linking GTP hydrolysis, phosphate release, and IF2 dissociation remain unresolved. Here, we use the α-form of E. coli IF2 in combination with time time-resolved cryo cryo-electron microscopy to fill these gaps. Our results reveal that the IF2 N-terminal domain serves as a stable anchor on the 30S subunit during initiation. We capture distinct conformational states of IF2 following GTP hydrolysis, providing structural snapshots that map the pathway from subunit joining to IF2 release. These findings deliver the first integrated structural framework for IF2 α–mediated initiation, offering time-resolved insight into factor dynamics that define the transition from initiation to elongation.
Displayed: 16/12/2025 22:18