Simple Pseudo-dipeptides with a P2′ Glutamate

A series of pseudo-peptides with general formula X-l-Glu-NH(2) (with X corresponding to an acyl moiety with a long aryl-alkyl side chain) have been synthesized, evaluated as inhibitors of matrix metalloproteases (MMPs), and found to display remarkable nanomolar affinity. The loss in potency associated with a substitution of the P(2)' l-glutamate by a l-glutamine corroborates the importance of a carboxylate at this position. The binding mode of some of these inhibitors was characterized in solution and by x-ray crystallography in complex with various MMPs. The x-ray crystal structures reveal an unusual binding mode with the glutamate side chain chelating the active site zinc ion. Competition experiments between these inhibitors and acetohydroxamic acid, a small zinc-binding molecule, are in accord with the crystallographic results. One of these pseudo-dipeptides displays potency and selectivity toward MMP-12 similar to the best MMP-12 inhibitors reported to date. This novel family of pseudo peptides opens new opportunities to develop potent and selective inhibitors for several metzincins.