Identification potential inhibitors against the Streptococcus quorum-sensing signal pathway

Streptococcal infections are common in human and antibiotics are frequently prescribed in clinical practice. However, infections caused by drug-resistant strains are particularly difficult to treat using common antibiotics. Hence, there is an urgent need for new antibiotics. Quorum sensing is a regulatory mechanism involving cell communication that is thought to play an important role in various bacterial infections, including those caused by Streptococcus. The ATP-binding cassette transporter ComA of Streptococcus is essential for quorum-sensing signal production. The inhibition of the ComA peptidase domain (ComA PEP) suppresses the quorum-sensing pathway and resulting changes in phenotype and/or behavior. Using virtual screening and molecular dynamics simulations, two promising candidate compounds, ZINC32918029 and ZINC6751571, were found. These compounds had similar binding modes and interactions to the experimentally determined reference inhibitor 6CH. However, a significantly stronger negative binding energy was achieved (-113.501 ± 15.312 KJ/mol and -103.153 ± 11.912 KJ/mol for ZINC32918029 and ZINC6751571, respectively). Molecular dynamics simulations also revealed that ZINC32918029 and ZINC6751571 had a strong affinity for ComA PEP. These results indicate that ZINC32918029 and ZINC6751571 are promising candidate inhibitors of the Streptococcus quorum-sensing pathway.Communicated by Ramaswamy H. Sarma.