In vitro enzyme characterization and several inhibitors for monkeypox virus core protease I7L.

Monkeypox is a zoonotic viral disease caused by the monkeypox virus, a member of the genus Orthopoxvirus within the family Poxviridae, which also includes the variola virus. On 14 August 2024, WHO Director-General declared monkeypox outbreak a public health emergency of international concern. Similar to variola virus core protease K7L, I7L could be identified as a promising target to fight against monkeypox virus. Our work provides a solid foundation as well as specific molecular tools (protease production methods, assay design, inhibitor design) that can now be used to probe the function of I7L in vitro. Notably, in this work, various reported covalent lead compounds for COVID-19 proteases were screened and A68, shikonin, and myricetin were identified as exhibiting high inhibitory activity against I7L. This work not only sheds light on effective inhibitors for the monkeypox virus core protease but also contributes to the broader search for antiviral agents targeting this enzyme.