Design and synthesis of a novel peptidomimetic inhibitor of HIV-1 Tat–TAR interactions: Squaryldiamide as a new potential bioisostere of unsubstituted guanidine

By performing RNA-targeted structure–activity relationship studies, we discovered a novel peptidomimetic containing squaryldiamide as a potential bioisostere replacement for guanidine that binds transactivation responsive RNA with high affinity.