Fellowship/Hines: Substrate and Inhibitor Specificity in Neuropeptidases

We have continued to investigate conditions for determining the structure of neurolysin complexed with a substrate or substrate analogue. Although the original crystal form under standard crystallization conditions failed toforro complex crystals in the past, we repeated these experiments with new inhibitors. Other systerrm have shown the cocrystals mayor may not form depending on the particular inhibitor in question. Factors such as inhibitor solubility in crystallization conditions, effect of inhibitor binding on protein conformation and the stability of the inhibitor may explain why some cocrystallize while others fail to do so. We received 6 new phosphinic inhibitors with different amino acid sequences from our new collaborators, Dr. Vincent Dive and Dr. Juri Jiracek. We have also received a proprietary inhibitor from a pharmaceutical company which is likely to inhibit neurolysin by a mechanism different from that of the phosphinic inhibitors. Whereas the phosphinic inhibitors have been shown in other zinc nietallopeptidases to coordinate to the catalytic zinc, the proprietary inhibitor binds elsewhere. Crystals grown in molar excess of these inhibitors were taiken to the Advanced Photon Source for data collectilon..