3zch

Ascorbate peroxidase W41A-H42M mutant

spinqualitylabelsall models 3zch, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3zch is a 1 chain structure with sequence from Glycine max. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: EPE, HEM, K, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q43758_SOYBN Publication Abstract from PubMed We have previously demonstrated (Badyal et al., J. Biol. Chem., 2006, 281, 24512) that removal of the active site tryptophan (Trp41) in ascorbate peroxidase increases the conformational mobility of the distal histidine residue (His42) and that His42 coordinates to the iron in the oxidised W41A enzyme to give a 6-coordinate, low-spin peroxidase. In this work, we probe the conformational flexibility of the active site in more detail. We examine whether other residues (Cys, Tyr, Met) can also ligate to the heme at position 42; we find that introduction of other ligating amino acids created a cavity in the heme pocket, but that formation of 6-coordinate heme is not observed. In addition, we examine the role of Asn-71, which hydrogen bonds to His42 and tethers the distal histidine in the active site pocket; we find that removal of this hydrogen bond increases the proportion of low-spin heme. We suggest that, in addition to its well-known role in facilitating the reaction with peroxide, His42 also plays a role in defining the shape and folding of the active site pocket. Probing the conformational mobility of the active site of a heme peroxidase.,Guimero A, Badyal SK, Leeks T, Moody PC, Raven EL Dalton Trans. 2012 Dec 3. PMID:23202589 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ascorbate peroxidase 3D structures

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