Ac-PHGGGWGQ-NH2, an octarepeat peptide fragment of prion, is a relatively effective ligand for Cu2+ ions. At a pH of about 7.4 the major binding sites involve the imidazole nitrogen and two amide nitrogens of (3)Gly and (4)Gly giving a CuH-2L species. The stability of the complex formed is similar to other peptides having a similar type of coordination. The NMR spectra indicate that in CuH-2L the complex side chain of the Trp residue is located very close to the metal ion. The geometry around the Cu2+ ion seems to be slightly distorted from the tetragonal one. In strongly basic solution the coordination involves an additional amide nitrogen. In CuH-2L, CuH-3L and CuH-4L complexes the amide nitrogens involved in the metal ion binding are those placed towards the C-terminal from the His residue. The N-terminal of the unprotected octapeptide is very effective in binding the Cu2+ ion although at high pH the imidazole nitrogen may not be involved in metal ion binding

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Bacterial infections are becoming increasingly difficult to treat due to the development and spread of antibiotic resistance. Therefore, identifying novel antibacterial targets and new antibacterial agents capable of treating infections from drug-resistant bacteria is of vital importance. Structurally simple, yet potent fusaricidin or LI-F class of natural products represents a particularly attractive source of candidates for the development of new antibacterial agents. We have synthesized eighteen fusaricidin/LI-F analogs and investigated the effect of their structure modification on conformation, serum stability, antibacterial activity and human cell toxicity. Our findings show that substitution of an ester bond in depsipeptides with an amide bond may afford equally potent analogs with improved stability and greatly decreased cytotoxicity. Lower overall hydrophobicity/amphiphilicity of amide analogs in comparison to their parent depsipeptides, as indicated by the HPLC retention times, may explain dissociation of antibacterial activity and human cell cytotoxicity. These results indicate that amide analogs may have significant advantages over fusaricidin/LI-F natural products and their depsipeptide analogs as lead structures for the development of new antibacterial agents.

Membrane-type 1 matrix metalloproteinase (MT1-MMP) is a zinc-dependent type-I transmembrane metalloproteinase involved in pericellular proteolysis, migration and invasion. Numerous substrates and binding partners have been identified for MT1-MMP, and its role in collagenolysis appears crucial for tumor invasion. However, development of MT1-MMP inhibitors must consider the substantial functions of MT1-MMP in normal physiology and disease prevention. The present review examines the plethora of MT1-MMP activities, how these activities relate to cancer initiation and progression, and how they can be monitored in real time. Examination of MT1-MMP activities and cell surface behaviors can set the stage for the development of unique, selective MT1-MMP inhibitors.

Research in the field of protease inhibitors is focused on obtaining potent, specific and protease-resistant inhibitors. To our knowledge, there are no reports in the literature that consider the application of N-substituted glycine residues (peptoid monomers) for the design of peptidomimetic protease inhibitors. We hereby present the chemical synthesis and kinetic properties of two new analogues of the trypsin inhibitor SFTI-1 modified at the P1 position. Substitution of Lys5 in SFTI-1 by N-(4-aminobutyl)-glycine and N-benzylglycine, which mimic Lys and Phe, respectively, made these analogues completely protease-resistant at their P1-P1' reactive sites. The analogues synthesised appeared to be potent inhibitors of bovine beta-trypsin and alpha-chymotrypsin. These noncovalent, competitive and selective peptide-peptoid hybrid (peptomeric) inhibitors might open the way to targeting unwanted proteolysis.