Substrate-based peptidomimetic inhibitors of the Murray Valley encephalitis virus NS2B/NS3 serine protease: a P1-P4 SAR study.

Murray Valley encephalitis is an infectious disease spread by a mosquito-borne virus endemic in Papua New Guinea and northern Australia. In the past decade, it has spread to various regions of Australia and there is currently no therapeutic treatment against this disease. An attractive drug target is the viral serine protease NS2B/NS3, a critical enzyme involved in viral replication. Herein, we report the inhibitory activities of 37 C-terminal agmatine peptidomimetic inhibitors which led to the design of a novel structurally-constrained competitive inhibitor 38 possessing a Ki of 2.5±0.5 μM. We believe our data provides crucial insights into the viral protease active site specificity which could be used to facilitate drug design against Murray Valley encephalitis viral infections.