Inhibition of chikungunya virus by picolinate that targets viral capsid protein

•Picolinic acid (PCA) binds to the hydrophobic pocket of CHIKV capsid protein (CP).•The binding constant KD (M) obtained for PCA was 2.1×10−7 M.•PCA inhibits CHIKV replication in Vero cells.•PCA potentially inhibits CHIKV via targeting protein-protein interactions of the CP.•Study suggests potential of pyridine ring compounds similar to PCA as antivirals.

The protein-protein interactions (PPIs) of the transmembrane glycoprotein E2 with the hydrophobic pocket on the surface of capsid protein (CP) plays a critical role in alphavirus life cycle. Dioxane based derivatives targeting PPIs have been reported to possess antiviral activity against Sindbis Virus (SINV), the prototype alphavirus. In this study, the binding of picolinic acid (PCA) to the conserved hydrophobic pocket of capsid protein was analyzed by molecular docking, isothermal titration calorimetry (ITC), surface plasmon resonance (SPR) and fluorescence spectroscopy. The binding constant KD obtained for PCA was 2.1×10−7 M. Additionally, PCA significantly inhibited CHIKV replication in infected Vero cells, decreasing viral mRNA and viral load as assessed by qRT-PCR and plaque reduction assay, respectively. This study is suggestive of the potential of pyridine ring compounds as antivirals against alphaviruses and may serve as the basis for the development of PCA based drugs against alphaviral diseases.