Related Experiment Video
Updated: Jun 22, 2026

Computational Prediction of Amino Acid Preferences of Potentially Multispecific Peptide-Binding Domains Involved in Protein-Protein Interactions
Published on: January 26, 2024
IpaB-IpgC interaction defines binding motif for type III secretion translocator
Michele Lunelli1, Ravi Kumar Lokareddy, Arturo Zychlinsky
1Department of Cellular Microbiology, Max Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany.
Invasion plasmid gene C (IpgC) chaperone binds Shigella virulence factors IpaB and IpaC. Structural analysis reveals how IpgC chaperones IpaB, aiding the design of anti-enterobacterial disease therapies.
Area of Science:
- Microbiology
- Structural Biology
- Pathogenesis
Background:
- Type III secretion systems (T3SS) are crucial for enterobacterial virulence, delivering effector proteins into host cells.
- Molecular chaperones, like Invasion plasmid gene C (IpgC), bind virulence factors in the bacterial cytosol, facilitating their secretion.
- IpgC specifically interacts with two essential Shigella virulence factors: invasion plasmid antigens (Ipa) B and C.
Purpose of the Study:
- To determine the crystal structure of IpgC alone and in complex with the chaperone binding domain (CBD) of IpaB.
- To elucidate the molecular mechanism by which IpgC chaperones IpaB.
Main Methods:
- X-ray crystallography to obtain structures of IpgC and the IpgC-IpaB CBD complex.
- Isothermal titration calorimetry (ITC) to analyze binding interactions and functional motifs.
Main Results:
- The crystal structure reveals IpgC captures the IpaB CBD in an extended conformation.
- Conserved residues within the IpgC cleft stabilize this interaction.
- A conserved sequence motif within the IpaB translocator class was identified and functionally validated by ITC.
Conclusions:
- The study provides structural insights into the chaperoning mechanism of T3SS translocators by IpgC.
- Understanding this interaction may facilitate the development of novel inhibitors targeting enterobacterial pathogenesis and diseases.
More Related Videos
08:07Identification of Inositol Phosphate or Phosphoinositide Interacting Proteins by Affinity Chromatography Coupled to Western Blot or Mass Spectrometry
Published on: July 26, 2019
11:33Monitoring the Assembly of a Secreted Bacterial Virulence Factor Using Site-specific Crosslinking
Published on: December 17, 2013
Related Concept Videos
Phosphoinositides and PIPs
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
Activation of Integrins
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
Assembly of Signaling Complexes
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
Protein-protein Interfaces
Mechanism of Conjugation
Intracellular Signaling Affects Focal Adhesions
Some...