X-ray crystallization studies of complexes of pseudolysin with small molecule inhibitors for potential therapeutic applications

Thermolysin-like proteases are secreted enzymes that degrade extracellular proteins and peptides for bacterial nutrition. Pseudolysin, the extracellular elastase of Pseudomonas aeruginosa, is a member of the thermolysin-like family of proteases. Pseudolys in has been identified as a key factor in the pathogenesis of P. aeruginosa infections because of its proteolytic activity on host tissues proteins. Indiscriminate proteolytic actvity of pseudolysin on host proteins results in severe hemorrhagic activity, skin damage, chronic ulcers and weakening of the host defense mechanisms. Therefore, pseudolysin is a potential target for developing drugs against Pseudomonas infections. Pseudolysin is a zinc-dependent protease whose active site is structurally similar to that of matrix metalloproteinases, matrixins. Using the three-dimensional structures of matrixins as template, we (Pharmacology and Toxicology Research Group, University of Tromsø,) used molecular modeling to identify small chemical compounds as poten tial inhibitors of pseudolysin proteolytic activity. The overall goal of the proposed project is to generate and analyze crystal complexes of pseudolysin with these small molecules to identify potential candidates for therapeutic applications. Dr. Odunuga (Chemistry Department, Stephen F. Austin State University, USA) will carry out the cloning, expression and purification of pseudolysin enzyme. In addition, he will be involved in screening and optimizing co-crystallization of pseudolysin with the small molecule inhibitors. The co-crystallization of pseudolysin-inhibtor complexes will be the first step in the designing of small molecule inhibitors that could be used to develop potent anti-infectives against P. aeruginosa infections mediated by pseudolysi n. The project will be carried out at the facility of the Pharmacology Research Group of the University of Tromsø. A visiting researcher grant is sought to enable Dr. Odunuga travel to Norway in the summer of 2011