Related Experiment Video

Updated: May 7, 2026

Advancing High-Resolution Imaging of Virus Assemblies in Liquid and Ice
08:31

Advancing High-Resolution Imaging of Virus Assemblies in Liquid and Ice

Published on: July 20, 2022

2.9K

Cryo-electron microscopy reveals the membrane insertion mechanism of V. cholerae hemolysin

Somnath Dutta1, Kalyan K Banerjee, Amar N Ghosh

  • 1a Division of Electron Microscopy , National Institute of Cholera and Enteric Diseases , P-33, C.I.T. Road, Scheme-XM, Beleghata, Kolkata , 700010 , India .

Journal of Biomolecular Structure & Dynamics
|October 10, 2013
PubMed

Insights

Vibrio cholerae hemolysin (HlyA), a pore-forming toxin, undergoes a conformational change upon interacting with cell membranes. This transition in the HlyA oligomer is crucial for its membrane insertion and pore formation.

Area of Science:

  • Microbiology
  • Structural Biology
  • Biochemistry

Background:

  • Vibrio cholerae hemolysin (HlyA) is a 65 kDa pore-forming toxin responsible for eukaryotic cell lysis.
  • HlyA forms heptameric channels in target cell plasma membranes.
  • A truncated variant (HlyA50) lacking the C-terminal domain shows significantly reduced pore-forming activity.

Purpose of the Study:

  • To investigate the structural changes of HlyA and HlyA50 upon interaction with erythrocyte stroma.
  • To elucidate the role of the conformational transition in HlyA-mediated membrane insertion.

Main Methods:

  • Cryo-electron microscopy was used to determine the 3D structures of HlyA and HlyA50.
  • Structures were determined in the presence of erythrocyte stroma to mimic membrane interaction.

Main Results:

  • HlyA oligomers showed a significant decrease in height and conformational changes in ring- and arm-like domains upon stroma interaction.
  • HlyA50 did not exhibit these conformational changes when interacting with stroma.
  • The observed conformational transition in HlyA was absent in the HlyA50 variant.

Conclusions:

  • The conformational transition of HlyA upon membrane interaction is critical for its insertion into the plasma membrane.
  • The C-terminal domain of HlyA plays a role in mediating this membrane-induced conformational change.
Keywords:
Vibrio cholerae hemolysincryo-electron microscopypore-forming toxinsingle particle analysis

More Related Videos

Do's and Don'ts of Cryo-electron Microscopy: A Primer on Sample Preparation and High Quality Data Collection for Macromolecular 3D Reconstruction09:25

Do's and Don'ts of Cryo-electron Microscopy: A Primer on Sample Preparation and High Quality Data Collection for Macromolecular 3D Reconstruction

Published on: January 9, 2015

46.5K
Preparing Lamellae from Vitreous Biological Samples Using a Dual-Beam Scanning Electron Microscope for Cryo-Electron Tomography07:00

Preparing Lamellae from Vitreous Biological Samples Using a Dual-Beam Scanning Electron Microscope for Cryo-Electron Tomography

Published on: August 5, 2021

5.3K

Related Concept Videos

Cryo-electron Microscopy01:28

Cryo-electron Microscopy

Conventional electron microscopy (EM) involves dehydration, fixation, and staining of biological samples, which distorts the native state of biological molecules and results in several artifacts. Also, the high-energy electron beam damages the sample and makes it difficult to obtain high-resolution images. These issues can be addressed using cryo-EM, which uses frozen samples and gentler electron beams. The technique was developed by Jacques Dubochet, Joachim Frank, and Richard Henderson, for...
3.2K
Cholera01:25

Cholera

Cholera is an acute gastrointestinal disease caused by the Gram-negative bacterium Vibrio cholerae. It is transmitted primarily via the fecal-oral route through the ingestion of contaminated water or food.Vibrio cholerae is a motile, Gram-negative bacterium of the family Vibrionaceae, primarily associated with waterborne outbreaks in areas with inadequate sanitation. Although over 200 serogroups of V. cholerae exist, only O1 and O139 are responsible for epidemic cholera. The O1 serogroup,...
159
Mechanisms of Membrane Domain Formation00:59

Mechanisms of Membrane Domain Formation

Different physical properties of lipids and proteins allow them to localize and form distinct islands or domains in the membrane. Some membrane domains are formed due to protein-protein interactions, whereas others are formed due to the presence of specific lipids such as sphingolipids and sterols—for example, large proteins, such as bacteriorhodopsin, aggregate and create distinct domains.
Another mechanism for membrane domain formation involves membrane proteins interacting with...
3.2K
Pinching-off of Coated Vesicles01:32

Pinching-off of Coated Vesicles

Vesicle budding is orchestrated by distinct cytosolic proteins such as adaptor proteins, coat proteins, and GTPases. To initiate vesicle budding, membrane-bending proteins containing crescent-shaped BAR domains bind to the lipid heads in the bilayer and distort the membrane to form a protein-coated vesicle bud. Adaptors proteins such as AP2 for clathrin-coated vesicles can nucleate on the deformed membrane. Finally, coat proteins such as clathrin or COPI and COPII assemble into a coat forming...
3.2K
Insertion of Single-pass Transmembrane Proteins in the RER01:26

Insertion of Single-pass Transmembrane Proteins in the RER

Integral membrane proteins are proteins adhered to the lipid bilayer of a cell organelle or membrane. They can be of two types: transmembrane integral proteins that span the lipid bilayer and monotopic proteins that are attached to either side of the membrane but do not pass through it.
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
13.1K