Evidence that enviroxime targets multiple components of the rhinovirus 14 replication complex.

Area of Science:

• Virology
• Drug Discovery
• Molecular Biology

Background:

• Enviroxime and analogs are effective inhibitors of rhinoviruses and enteroviruses in cell culture.
• Previous studies suggested the viral nonstructural protein 3A(B) is the target of enviroxime.
• Rhinoviruses and enteroviruses are significant human pathogens.

Purpose of the Study:

• To confirm the link between rhinovirus 14 3A(B) domains and enviroxime's inhibitory function.
• To investigate the molecular mechanism of enviroxime's antiviral activity.
• To identify potential direct interactions between enviroxime and viral or host factors.

Main Methods:

• Site-directed mutagenesis and selection of spontaneous rhinovirus 14 mutants.
• Production of recombinant 3A and 3AB proteins for biochemical assays.
• Testing for direct binding of enviroxime to viral and host proteins, RNA binding, protein-protein interactions, membrane association, and protease cleavage.

Main Results:

• Enviroxime's target was confirmed to involve domains in rhinovirus 14 3A(B).
• Direct binding of enviroxime to viral or host proteins was not demonstrated.
• Enviroxime did not interfere with 3AB's RNA binding, 3D polypeptide interaction, membrane association, or 3C protease cleavage.
• An enviroxime-resistant mutant with multiple mutations was identified.

Conclusions:

• Enviroxime likely targets a complex of viral proteins and/or cellular factors.
• The complex inhibition mechanism may explain the low levels of viral resistance to enviroxime.
• Further research is needed to elucidate the precise composition and function of the targeted complex.