The Cyclic Dipeptide Cyclo(Phe-Pro) Inhibits Cholera Toxin and Toxin-Coregulated Pilus Production in O1 El Tor <i>Vibrio cholerae</i>

Abstract

Cyclo(Phe-Pro) is a cyclic dipeptide produced by multiple Vibrio species. In this work, we present evidence that cyclo(Phe-Pro) inhibits the production of the virulence factors cholera toxin (CT) and toxin-coregulated pilus (TCP) in O1 El Tor Vibrio cholerae strain N16961 during growth under virulence gene-inducing conditions. The cyclo(Phe-Pro) inhibition of CT and TCP production correlated with reduced transcription of the virulence regulator tcpPH and was alleviated by overexpression of tcpPH.