Serine/threonine kinase of Mpox virus: computational modeling and structural analysis

Kinases catalyze phosphoryl transfer from a nucleoside triphosphate (usually ATP) to an amino acid on a protein for activation purposes. Although kinases are well-appreciated drug targets in different viruses and cancers, these enzymes in poxviruses received limited attention from the research community. In poxvirus, the production of infectious particles in the infected cells depends on a serine/threonine protein kinase (STK) that activates proteins implicated in the assembly of new virions. This work aimed to elucidate the structure and dynamics of the major kinase STK from Mpox virus (Orthopoxvirus). A state-of-the-art computational approach was employed to decipher the structure and dynamics of the STK using AlphaFold2 and molecular dynamics (MD) simulations. Although the predicted structure showed an atypical kinase, the overall structural fold is conserved. Binding free energy calculations via Molecular Mechanics/Generalized Born and Surface Area (MM/GBSA) determined the hotspot residues contributing to binding of ATP. The structural analysis in this work provides insights into the structure and behavior of STK in Mpox virus and possibly its closest members of Poxviridae. These findings also set the basis for setting up a thorough experimental investigation to understand the enzymatic mechanism, peptide substrate binding, and the development of small-molecule inhibitors against this kinase.