<p>Discovering
efficient drugs and identifying target proteins are still an unmet but urgent need
for curing COVID-19. Protein structure based docking is a widely applied
approach for discovering active compounds against drug targets and for
predicting potential targets of active compounds. However, this approach has
its inherent deficiency caused by, e.g., various different conformations with
largely varied binding pockets adopted by proteins, or the lack of true target
proteins in the database. This deficiency may result in false negative results.
As a complementary approach to the protein structure based platform for
COVID-19, termed as D3Docking in our recent work, we developed the ligand-based
method, named D3Similarity, which is based on the molecular similarity
evaluation between the submitted molecule(s) and those in an active compound
database. The database is constituted by all the reported bioactive molecules against
the coronaviruses SARS, MERS and SARS-CoV-2, some of which have target or
mechanism information but some don’t. Based on the two-dimensional and
three-dimensional similarity evaluation of molecular structures, virtual
screening and target prediction could be performed according to similarity ranking
results. With two examples, we demonstrated the reliability and efficiency of D3Similarity
for drug discovery and target prediction against COVID-19. D3Similarity is
available free of charge at <a href="https://www.d3pharma.com/D3Targets-2019-nCoV/D3Similarity/index.php">https://www.d3pharma.com/D3Targets-2019-nCoV/D3Similarity/index.php</a>.</p>