ORF8a of SARS-CoV forms an ion channel: Experiments and molecular dynamics simulations

ORF8a protein is 39 residues long and contains a single transmembrane domain. The protein is synthesized using solid phase peptide synthesis and reconstituted into artificial lipid bilayers that forms cation-selective ion channels with a main conductance level of 8.9 ± 0.8 pS at elevated temperature (38.5 °C). Computational modeling studies including multi nanosecond molecular dynamics simulations in a hydrated POPC lipid bilayer are done with a 22 amino acid transmembrane helix to predict a putative homooligomeric helical bundle model. A structural model of a pentameric bundle is proposed with cysteines, serines and threonines facing the pore.

Research Highlights► ORF 8a (39 amino acids) of SARS-CoV forms an ion channel in artificial bilayers. ► Slight cation-selectivity with a main conductance level of 8.9 ± 0.8 pS at elevated temperature. ► Using computational modeling a pentameric assembly is proposed. ► Computational models propose cysteines, serines and threonines facing the pore.