This is the N-terminal domain found in Proline utilization A (PutA) proteins. Proline utilization A (PutA) is a flavoprotein that has mutually exclusive roles as a transcriptional repressor of the put regulon and a membrane-associated enzyme that catalyzes the oxidation of proline to glutamate [4]. The N-terminal region carries the flavoenzyme proline dehydrogenase (PRODH) domain which catalyzes the 2-electron oxidation of proline with the concomitant reduction of a flavin cofactor [9].

1: Structures of the Escherichia coli PutA proline dehydrogenase domain in complex with competitive inhibitors. Zhang M, White TA, Schuermann JP, Baban BA, Becker DF, Tanner JJ; Biochemistry. 2004;43:12539-12548. PMID:15449943

2: Redox-induced changes in flavin structure and roles of flavin N(5) and the ribityl 2'-OH group in regulating PutA--membrane binding. Zhang W, Zhang M, Zhu W, Zhou Y, Wanduragala S, Rewinkel D, Tanner JJ, Becker DF; Biochemistry. 2007;46:483-491. PMID:17209558

3: A conserved active site tyrosine residue of proline dehydrogenase helps enforce the preference for proline over hydroxyproline as the substrate. Ostrander EL, Larson JD, Schuermann JP, Tanner JJ; Biochemistry. 2009;48:951-959. PMID:19140736

4: The structure of the proline utilization a proline dehydrogenase domain inactivated by N-propargylglycine provides insight into conformational changes induced by substrate binding and flavin reduction. Srivastava D, Zhu W, Johnson WH Jr, Whitman CP, Becker DF, Tanner JJ; Biochemistry. 2010;49:560-569. PMID:19994913

5: Involvement of the beta3-alpha3 loop of the proline dehydrogenase domain in allosteric regulation of membrane association of proline utilization A. Zhu W, Haile AM, Singh RK, Larson JD, Smithen D, Chan JY, Tanner JJ, Becker DF; Biochemistry. 2013;52:4482-4491. PMID:23713611

6: Structure of the proline dehydrogenase domain of the multifunctional PutA flavoprotein. Lee YH, Nadaraia S, Gu D, Becker DF, Tanner JJ; Nat Struct Biol. 2003;10:109-114. PMID:12514740

7: Crystal structure of the bifunctional proline utilization A flavoenzyme from Bradyrhizobium japonicum. Srivastava D, Schuermann JP, White TA, Krishnan N, Sanyal N, Hura GL, Tan A, Henzl MT, Becker DF, Tanner JJ; Proc Natl Acad Sci U S A. 2010;107:2878-2883. PMID:20133651

8: Kinetic and structural characterization of tunnel-perturbing mutants in Bradyrhizobium japonicum proline utilization A. Arentson BW, Luo M, Pemberton TA, Tanner JJ, Becker DF; Biochemistry. 2014;53:5150-5161. PMID:25046425

9: Structure, function, and mechanism of proline utilization A (PutA). Liu LK, Becker DF, Tanner JJ; Arch Biochem Biophys. 2017; [Epub ahead of print] PMID:28712849