Light-controlled DNA binding of bisbenzamidines.

Caging of the amidinium moieties of two representative bisbenzamidine DNA binders with suitable photoresponsive protecting groups suppresses their DNA-binding, which can then be fully recovered upon irradiation with UV light that removes the caging groups, regenerating the parent compounds. Moreover, a caged aza-pentamidine (©1a) is inert against Candida albicans, but displays a potent growth inhibitory activity after irradiation with UV light.