3249-Pos B404

Coronaviruses (CoV) are pathogens that cause common colds, bronchiolitis and acute respiratory distress syndrome. In fact, their relevance increased when the causative agent of the severe acute respiratory syndrome (SARS) was identified as a CoV. CoV E protein is a small transmembrane protein of between 76-109 amino acids in length that modulates coronavirus morphogenesis, tropism and virulence \[1\].

We have reported that E protein conductance and ion selectivity were controlled by the lipid composition of the membrane \[2\]. These results indicated that, most likely, lipid molecules assembled with the peptide oligomers to form the channel.

Here we provide additional evidences of the functional involvement of lipids in the channel structure. The influence of lipid molecules on E protein channel transport properties was investigated focusing on the salt concentration dependence of the E protein conductance and the pH dependence of the channel ion selectivity.

The channel conductance in neutral bilayers increased with the electrolyte concentration whereas in charged bilayers it is approximately proportional to the square root of salt concentration, which reveals an electrostatic contribution from the lipid charge. In regard to pH dependence of ion selectivity, in uncharged bilayers the titration curve shows a single transition that corresponds to E protein residue titration, whereas in charged bilayers a second transition is observed, which presumably corresponds to lipid groups titration.

These results support the previous hypothesis that the lipids are functionally involved in E protein ion channel activity, forming a protein-lipid pore, a novel concept for CoV E protein ion channel entity.

\[1\] DeDiego, M.L., et al 2008. Virology 376, 379-389.

\[2\] Verdiá-Báguena C., et al. 2012. Virology. 432: 485-494.
