Abstract: A model structure of sub-domain IIId of the hepatitis C virus internal ribosome entry site has been elucidated. The invention provides an in silico method for identifying a compound that interacts with sub-domain IIId, comprising the steps of: (a) providing atomic co-ordinates of said sub-domain IIId in a storage medium on a Computer; and (b) using said computer to apply molecular modelling techniques to said co-ordinates. Suitable methods include de novo compound design, use of a pharmacophore, and automated docking algorithms.