2g37
From Proteopedia
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Structure of Thermus thermophilus L-proline dehydrogenase
Overview
Proline dehydrogenase (PRODH) and pyrroline-5-carboxylate dehydrogenase, (P5CDH) catalyze the two-step oxidation of proline to glutamate. They are, distinct monofunctional enzymes in all eukaryotes and some bacteria, but, are fused into bifunctional enzymes known as Proline utilization A (PutA), in other bacteria. Here we report the first structure and biochemical data, for a monofunctional PRODH. The 2.0 A resolution structure of Thermus, thermophilus PRODH reveals a distorted (betaalpha)(8) barrel catalytic, core domain and a hydrophobic alpha-helical domain located above the, carboxyl terminal ends of the strands of the barrel. Although the, catalytic core is similar to that of the PutA PRODH domain, the FAD, conformation of T. thermophilus PRODH is remarkably different and likely, reflects unique requirements for membrane association and communication, with P5CDH. Also, the FAD of T. thermophilus PRODH is highly solvent, exposed compared to PutA due to a 4-A shift of helix 8. Structure-based, sequence analysis of the PutA/PRODH family led us to identify 9 conserved, motifs involved in cofactor and substrate recognition. Biochemical studies, show that the midpoint potential of the FAD is -75 mV and the kinetic, parameters for proline are K(m)=27 mM and k(cat)=13 s (-1)., 3,4-dehydro-L-proline was found to be an efficient substrate and, L-tetrahydro-2-furoic acid is a competitive inhibitor (K(I)=1.0 mM)., Finally, we demonstrate that PRODH reacts with O(2) producing superoxide., This is significant because superoxide production underlies the role of, human PRODH in p53-mediated apoptosis, implying commonalities between, eukaryotic and bacterial monofunctional PRODHs.
About this Structure
2G37 is a Single protein structure of sequence from Thermus thermophilus with and as ligands. Active as Proline dehydrogenase, with EC number 1.5.99.8 Full crystallographic information is available from OCA.
Reference
Structure and kinetics of monofunctional proline dehydrogenase from thermus thermophilus., White TA, Krishnan N, Becker DF, Tanner JJ, J Biol Chem. 2007 Mar 7;. PMID:17344208
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