title: Structure of the proline dehydrogenase domain of the multifunctional PutA flavoprotein.
abstract: The PutA flavoprotein from Escherichia coli plays multiple roles in proline catabolism by functioning as a membrane-associated bi-functional enzyme and a transcriptional repressor of proline utilization genes. The human homolog of the PutA proline dehydrogenase (PRODH) domain is critical in p53-mediated apoptosis and schizophrenia. Here we report the crystal structure of a 669-residue truncated form of PutA that shows both PRODH and DNA-binding activities, representing the first structure of a PutA protein and a PRODH enzyme from any organism. The structure is a domain-swapped dimer with each subunit comprising three domains: a helical dimerization arm, a 120-residue domain containing a three-helix bundle similar to that in the helix-turn-helix superfamily of DNA-binding proteins and a beta/alpha-barrel PRODH domain with a bound lactate inhibitor. Analysis of the structure provides insight into the mechanism of proline oxidation to pyrroline-5-carboxylate, and functional studies of a mutant protein suggest that the DNA-binding domain is located within the N-terminal 261 residues of E. coli PutA.
authors.affiliation: Department of Chemistry and Biochemistry, University of Missouri-Columbia, 65211, USA.
authors.forename: Yong-Hwan
authors.initials: YH
authors.lastname: Lee
authors.forename: Shorena
authors.initials: S
authors.lastname: Nadaraia
authors.forename: Dan
authors.initials: D
authors.lastname: Gu
authors.forename: Donald F
authors.initials: DF
authors.lastname: Becker
authors.forename: John J
authors.initials: JJ
authors.lastname: Tanner
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry; D019281:Dimerization; D029968:Escherichia coli Proteins / Q000737:chemistry; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry*; D008958:Models, Molecular; D011394:Proline Oxidase / Q000737:chemistry*; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; C080683:PutA protein, Bacteria; D011394:Proline Oxidase