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Updated: Jun 26, 2026
09:49
Sedimentation Equilibrium of a Small Oligomer-forming Membrane Protein: Effect of Histidine Protonation on Pentameric Stability
Published on: April 2, 2015
Structural Bases for the Unconventional Activity of a Viroporin Channel
Brian Wiley1, Eneko Largo2, Laura Nabais1
1Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AX, U.K.
Biochemistry
|June 25, 2026
Summary
Classical Swine Fever Virus p7 viroporin forms ion channels with varying sizes. Molecular dynamics simulations reveal how oligomeric state and helix packing influence pore dimensions and hydration, impacting membrane permeability.
Area of Science:
- Structural biology
- Virology
- Biophysics
Background:
- Viroporins are viral proteins that disrupt cell membrane permeability, influencing viral infection cycles.
- The Classical Swine Fever Virus p7 protein exhibits unconventional ion channel behavior, posing challenges for therapeutic targeting.
- Understanding the structural basis of p7's atypical channel activity is crucial for developing antiviral strategies.
Purpose of the Study:
- To elucidate the structural basis and mechanisms underlying the atypical ion channel activity of the Classical Swine Fever Virus p7 viroporin.
- To investigate how structural architecture and oligomeric state influence pore formation and ion conductivity.
- To provide a structural framework for interpreting p7's experimentally observed capacity to induce multiple conductance states.
Main Methods:
- All-atom molecular dynamics (MD) simulations were employed to study the behavior of p7 monomers and oligomers within ER-like lipid bilayers.
- AlphaFold-predicted CSFV p7 hexamer structures were used as a starting point to generate extended transmembrane hairpin (TMH) protomers.
- Oligomers of varying stoichiometry (pentamers, hexamers, heptamers) were assembled, with a focus on two hexameric models (TMH1 and TMH2_6) and a heptameric model (TMH2_7).
Main Results:
- Simulations revealed that both structural architecture and oligomeric state dictate pore organization and ion accessibility in ER-like membranes.
- TMH1 hexamers and TMH2_7 heptamers formed wide, hydrated pores, while TMH2_6 hexamers exhibited narrower, more compact hydrated pores.
- TMH2_5 pentamers were largely nonconductive, indicating that oligomeric state is critical for channel formation.
- Dynamic interactions between transmembrane helices and the number of protomers were identified as key factors in pore formation and function.
Conclusions:
- Variations in the oligomeric state and helix packing of CSFV p7 can generate ion channels with distinct dimensions and hydration properties.
- These findings offer a structural explanation for p7's ability to form multiple conductance states and mediate size-selective membrane permeabilization.
- The study provides critical insights into viroporin channel mechanisms, potentially guiding the development of novel antiviral therapeutics targeting membrane disruption.
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