This study aims at the identification of novel structural features on the surface of the Zn-dependent metalloprotease lethal factor (LF) from anthrax onto which to design novel and selective inhibitors. We report that by targeting an unexplored region of LF that exhibits ligand-induced conformational changes, we could obtain inhibitors with at least 30-fold LF selectivity compared to two other most related human metalloproteases, MMP-2 and MMP-9. Based on these results, we propose a novel pharmacophore model that, together with the preliminarily identified compounds, should help the design of more potent and selective inhibitors against anthrax.