Exploring the Requirements for the Hydrophobic Scaffold and Polar Amine in Inhibitors of M2 from Influenza A Virus

Inhibitors targeting the influenza A virus M2 (A/M2) proton channel have lost their effectiveness due to widespread resistance. As a first step in the development of new inhibitors that address this problem, we have screened several focused collections of small molecules using two-electrode voltage patch clamp assays (TEVC) on Xenopus laevis oocytes. Diverse head groups and scaffolds of A/M2 inhibitors have been explored. It has been found that not only amine but also hydroxyl, aminooxyl, guanidine, and amidine compounds are active against the A/M2 proton channel. Moreover, the channel is able to accommodate a wide range of structural variation in the apolar scaffold. This study offers information to guide the next generation of A/M2 proton channel inhibitor design.