4env

Structure of the S234I variant of E. coli KatE

spinqualitylabelsall models 4env, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4env is a 4 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: HDD, HEM Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [CATE_ECOLI] Decomposes hydrogen peroxide into water and oxygen; serves to protect cells from the toxic effects of hydrogen peroxide. Publication Abstract from PubMed The main channel for H(2)O(2) access to the heme cavity in large subunit catalases is twice as long as in small subunit catalases and is divided into two distinct parts. Like small subunit catalases, the 15A of the channel adjacent to the heme has a predominantly hydrophobic surface with only weak water occupancy, but the next 15A extending to the protein surface is hydrophilic and contains a complex water matrix in multiple passages. At the approximate junction of these two sections are a conserved serine and glutamate that are hydrogen bonded and associated with H(2)O(2) in inactive variants. Mutation of these residues changed the dimensions of the channel, both enlarging and constricting it, and also changed the solvent occupancy in the hydrophobic, inner section of the main channel. Despite these structural changes and the prominent location of the residues in the channel, the variants exhibited less than a 2-fold change in the k(cat) and apparent K(M) kinetic constants. These results reflect the importance of the complex multi-passage structure of the main channel. Surprisingly, mutation of either the serine or glutamate to an aliphatic side chain interfered with heme oxidation to heme d. Influence of main channel structure on H(2)O(2) access to the heme cavity of catalase KatE of Escherichia coli.,Jha V, Chelikani P, Carpena X, Fita I, Loewen PC Arch Biochem Biophys. 2012 Oct 1;526(1):54-9. doi: 10.1016/j.abb.2012.06.010., Epub 2012 Jul 20. PMID:22820098 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Catalase 3D structures

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