5ux5 | pdb_00005ux5

Structure of Proline Utilization A (PutA) from Corynebacterium freiburgense

spinqualitylabelsall models 5ux5, resolution 2.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5ux5 is a 4 chain structure with sequence from Corynebacterium freiburgense. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.7Å Ligands: FAD, NAD, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A1X8XLF1_9CORY Publication Abstract from PubMed The bifunctional flavoenzyme proline utilization A (PutA) catalyzes the two-step oxidation of proline to glutamate using separate proline dehydrogenase (PRODH) and L-glutamate-gamma-semialdehyde dehydrogenase (GSALDH) active sites. Because PutAs catalyze sequential reactions, they are good systems for studying how metabolic enzymes communicate via substrate channeling. Although mechanistically similar, PutAs vary widely in domain architecture, oligomeric state, and quaternary structure, and these variations represent different structural solutions to the problem of sequestering a reactive metabolite. Here, we studied PutA from Corynebacterium freiburgense (CfPutA), which belongs to the uncharacterized 3B class of PutAs. A 2.7 A resolution crystal structure showed the canonical arrangement of PRODH, GSALDH, and C-terminal domains, including an extended interdomain tunnel associated with substrate channeling. The structure unexpectedly revealed a novel open conformation of the PRODH active site, which is interpreted to represent the non-activated conformation, an elusive form of PutA that exhibits suboptimal channeling. Nevertheless, CfPutA exhibited normal substrate-channeling activity, indicating it isomerizes into the active state under assay conditions. Sedimentation velocity experiments provided insight into the isomerization process, showing that CfPutA dimerizes in the presence of a proline analog and NAD+ These results are consistent with the morpheein model of enzyme hysteresis, in which substrate binding induces conformational changes that promote assembly of a high-activity oligomer. Finally, we used domain deletion analysis to investigate the function of the C-terminal domain. Although this domain contains neither catalytic residues nor substrate sites, its removal impaired both catalytic activities, suggesting it may be essential for active-site integrity. Structure and characterization of a class 3B proline utilization A: ligand-induced dimerization and importance of the C-terminal domain for catalysis.,Korasick D, Gamage TT, Christgen S, Stiers KM, Beamer LJ, Henzl MT, Becker DF, Tanner JJ J Biol Chem. 2017 Apr 18. pii: jbc.M117.786855. doi: 10.1074/jbc.M117.786855. PMID:28420730 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Proline utilization A

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