5kq3

Crystal structure of the D141A/Q233E variant of catalase-peroxidase from B. pseudomallei

spinqualitylabelsall models 5kq3, resolution 1.85Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5kq3 is a 2 chain structure with sequence from Burkholderia pseudomallei 1710b. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.85Å Ligands: CL, HEM, MPD, NA, OXY, PO4, TOX Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function KATG_BURP1 Bifunctional enzyme with both catalase and broad-spectrum peroxidase activity. Publication Abstract from PubMed The unusual Met-Tyr-Trp adduct composed of cross-linked side chains along with an associated mobile Arg is essential for catalase activity in catalase-peroxidases. In addition, acidic residues in the entrance channel, in particular an Asp and a Glu approximately 7 and approximately 15 A, respectively, from the heme, significantly enhance catalase activity. The mechanism by which these channel carboxylates influence catalase activity is the focus of this work. Seventeen new variants with fewer and additional acidic residues have been constructed and characterized structurally and for enzymatic activity, revealing that their effect on activity is roughly inversely proportional to their distance from the heme and adduct, suggesting that the electrostatic potential of the heme cavity may be affected. A discrete group of protonable residues are contained within a 15 A sphere surrounding the heme iron, and a computational analysis reveals that the pKa of the distal His112, alone, is modulated within the pH range of catalase activity by the remote acidic residues in a pattern consistent with its protonated form having a key role in the catalase reaction cycle. The electrostatic potential also impacts the catalatic reaction through its influence on the charged status of the Met-Tyr-Trp adduct. The Catalase Activity of Catalase-Peroxidases Is Modulated by Changes in the pKa of the Distal Histidine.,Machuqueiro M, Victor B, Switala J, Villanueva J, Rovira C, Fita I, Loewen PC Biochemistry. 2017 Apr 20. doi: 10.1021/acs.biochem.6b01276. PMID:28409923 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Catalase 3D structures

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