C450-0730 is an antagonist targeting the AHL membrane-bound sensor kinase and is an antagonist of the nine-transmembrane protein LuxN of Vibrio harveyi . C450-0730 competitively binds to the LuxN AI-1 binding site and specifically antagonizes the LuxN/AI-1 quorum sensing signal in Vibrio harveyi. The inhibitory activity of C450-0730 against LuxNI209F was not significant[1].