4nmb | pdb_00004nmb

Crystal structure of proline utilization A (PutA) from Geobacter sulfurreducens PCA in complex with L-lactate

spinqualitylabelsall models 4nmb, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4nmb is a 2 chain structure with sequence from Geobacter sulfurreducens PCA. This structure supersedes the now removed PDB entry 4f9i. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 2OP, FAD, MES Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q746X3_GEOSL Publication Abstract from PubMed Proline utilization A (PutA) proteins are bifunctional peripheral membrane flavoenzymes that catalyze the oxidation of l-proline to l-glutamate by the sequential activities of proline dehydrogenase and aldehyde dehydrogenase domains. Located at the inner membrane of Gram-negative bacteria, PutAs play a major role in energy metabolism by coupling the oxidation of proline imported from the environment to the reduction of membrane-associated quinones. Here, we report seven crystal structures of the 1,004-residue PutA from Geobacter sulfurreducens, along with determination of the protein oligomeric state by small-angle X-ray scattering and kinetic characterization of substrate channeling and quinone reduction. The structures reveal an elaborate and dynamic tunnel system featuring a 75-A-long tunnel that links the two active sites and six smaller tunnels that connect the main tunnel to the bulk medium. The locations of these tunnels and their responses to ligand binding and flavin reduction suggest hypotheses about how proline, water, and quinones enter the tunnel system and where l-glutamate exits. Kinetic measurements show that glutamate production from proline occurs without a lag phase, consistent with substrate channeling and implying that the observed tunnel is functionally relevant. Furthermore, the structure of reduced PutA complexed with menadione bisulfite reveals the elusive quinone-binding site. The benzoquinone binds within 4.0 A of the flavin si face, consistent with direct electron transfer. The location of the quinone site implies that the concave surface of the PutA dimer approaches the membrane. Altogether, these results provide insight into how PutAs couple proline oxidation to quinone reduction. Structures of the PutA peripheral membrane flavoenzyme reveal a dynamic substrate-channeling tunnel and the quinone-binding site.,Singh H, Arentson BW, Becker DF, Tanner JJ Proc Natl Acad Sci U S A. 2014 Mar 4;111(9):3389-94. doi:, 10.1073/pnas.1321621111. Epub 2014 Feb 18. PMID:24550478 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Proline utilization A

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