Computational Studies of Proton Transport through the M2 Channel

TitleComputational Studies of Proton Transport through the M2 Channel
Publication TypeJournal Article
Year of Publication2003
AuthorsWu, Y, Voth, GA
JournalFEBS Lett
KeywordsComputer Simulation DNA/chemistry Histidine/chemistry Hydrogen-Ion Concentration Ions Magnetic Resonance Spectroscopy Models, Molecular Peptides/chemistry Protein Conformation Protein Structure, Secondary *Protons Tryptophan/chemistry Ultraviolet Rays Viral Matrix Proteins/*chemistry/metabolism

The M2 ion channel is an essential component of the influenza A virus. This low-pH gated channel has a high selectivity for protons. Evidence from various experimental data has indicated that the essential structure responsible for the channel is a parallel homo-tetrameric alpha-helix bundle having a left-handed twist with each helix tilted with respect to the membrane normal. A backbone structure has been determined by solid state nuclear magnetic resonance (NMR). Though detailed structures for the side chains are not available yet, evidence has indicated that His37 and Trp41 in the alpha-helix are implicated in the local molecular structure responsible for the selectivity and channel gate. More definitive conformations for the two residues were recently suggested based on the known backbone structure and recently obtained NMR data. While two competitive proton-conductance mechanisms have been proposed, the actual proton-conductance mechanism remains an unsolved problem. Computer simulations of an excess proton in the channel and computational studies of the His37/Trp41 conformations have provided insights into these structural and mechanism issues.