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Gianti E , Carnevale V , DeGrado WF , Klein ML , Fiorin G
Hydrogen-bonded water molecules in the M2 channel of the influenza A virus guide the binding preferences of ammonium-based inhibitors
J Phys Chem B. 2015 Jan 22;119(3) :1173-83
PMID: 25353315    PMCID: PMC4386636   
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The tetrameric M2 proton channel of influenza A virus is an integral membrane protein responsible for the acidification of the viral interior. Drugs such as amantadine target the transmembrane region of wild type M2 by acting as pore blockers. However, a number of mutations affecting this domain confer drug resistance, prompting the need for alternative inhibitors. The availability of high-resolution structures of drug-bound M2, paired with computational investigations, revealed that inhibitors can bind at different sites, and provided useful insights in understanding the principles governing proton conduction. Here, we investigated by computation the energetic and geometric factors determining the relative stability of pore blockers at individual sites of different M2 strains. We found that local free energy minima along the translocation pathway of positively charged chemical species correspond to experimentally determined binding sites of inhibitors. Then, by examining the structure of water clusters hydrating each site, as well as of those displaced by binding of hydrophobic scaffolds, we predicted the binding preferences of M2 ligands. This information can be used to guide the identification of novel classes of inhibitors.
Gianti, Eleonora Carnevale, Vincenzo DeGrado, William F Klein, Michael L Fiorin, Giacomo R01 GM056423/GM/NIGMS NIH HHS/United States Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. United States J Phys Chem B. 2015 Jan 22;119(3):1173-83. doi: 10.1021/jp506807y. Epub 2014 Nov 11.