Development of anti-coxsackievirus agents targeting 3C protease

Peptidomimetic anti-viral agents against Coxsackievirus B3 (CVB3) were developed using a strategy involving the inhibition of 3C protease (CVB3 3C(pro)), a target for CVB3-mediated myocarditis or pericarditis. In an attempt to improve the inhibitory activity against CVB3, a variety of hetero-aromatic groups were incorporated into the α,β-unsaturated ester as Michael acceptor moiety, which is the position of interaction with the cysteine moiety in the P1' active site of CVB3 3C(pro). Among these hetero-aromatic groups, the quinoline analogs 9c and 9e, with IC(50) values of 250 and 130 nM as determined from an enzyme assay, significantly inhibited the CVB3-mediated cell cytotoxicity, indicating parallel anti-viral activities. A comparison of the binding modes of the potent inhibitor 9e and the relatively weak inhibitor 9n was explored in a molecular docking study, which revealed that compound 9n lacked hydrogen bonds in its interactions with Gly129, 128, and 145.