| E. coli proline dehydrogenase (PRODH) catalyzes the oxidization of proline to Delta'-pyrroline-5-carboxylate (PSC), which is the initial step in the utilization of proline as a source of energy and nitrogen. It is known that this reaction includes hydride transfer from proline to the cofactor FAD, but the relationship between enzyme structure and its function is unclear. The goal of this research is to provide structural insights into the catalytic mechanism of PRODH.; Crystallography is the main method used in this study. Four structures of inhibited PRODH were obtained by co-crystallization and the reduced state was captured by soaking oxidized crystals in sodium dithionite. The structures reveal the details of inhibitor and substrate recognition. Different conformations of the cofactor, FAD, are observed in crystal structures of different oxidization states. The observed conformational change caused by FAD reduction is postulated to stabilize the reduced cofactor and facilitate product release. |
