Virtual Screening

This chapter focuses on requirements and aspects of virtual screening, which aims to explore large chemical databases at minimal costs. The used rationale either is the known protein structure of the target (structure-based virtual screening) or employs information from known actives (ligand-based virtual screening). Depending on the actual knowledge and goal of the virtual screening, methods and databases have to be carefully chosen. Successful virtual screening applications require the definition and the careful validation of the virtual screening strategy. Important aspects of the virtual screening strategy comprise questions like which virtual screening methods are used, whether these methods are applied in parallel or used sequentially in a cascaded virtual screening, and how many compounds can be selected for biological testing. The concepts developed for virtual screening find application in related scientific areas, for example, in chemogenomics or in in silico profiling applications.