1qt4

T26Q MUTANT OF T4 LYSOZYME

spinqualitylabelsall models 1qt4, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1qt4 is a 1 chain structure with sequence from Bpt4. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: BME, CL Related: 1qtv, 1qtz, 1qt3, 1qt5, 1qt6, 1qt7, 1qt8 Activity: Lysozyme, with EC number 3.2.1.17 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [LYS_BPT4] Helps to release the mature phage particles from the cell wall by breaking down the peptidoglycan. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed In contrast to hen egg-white lysozyme, which retains the beta-configuration of the substrate in the product, T4 lysozyme (T4L) is an inverting glycosidase. The substitution Thr-26 --> His, however, converts T4L from an inverting to a retaining enzyme. It is shown here that the Thr-26 --> His mutant is also a transglycosidase. Indeed, the transglycosylation reaction can be more effective than hydrolysis. In contrast, wild-type T4L has no detectable transglycosidase activity. The results support the prior hypothesis that catalysis by the Thr-26 --> His mutant proceeds via a covalent intermediate. Further mutations (Glu-11 --> His, Asp-20 --> Cys) of the T26H mutant lysozyme indicate that the catalytic mechanism of this mutant requires Glu-11 as a general acid but Asp-20 is not essential. The results help provide an overall rationalization for the activity of glycosidases, in which a highly conserved acid group (Glu-11 in T4L, Glu-35 in hen egg-white lysozyme) on the beta-side of the substrate acts as a proton donor, whereas alterations in the placement and chemical identity of residues on the alpha-side of the substrate can lead to catalysis with or without retention of the configuration, to transglycosidase activity, or to the formation of a stable enzyme-substrate adduct. Structural basis of the conversion of T4 lysozyme into a transglycosidase by reengineering the active site.,Kuroki R, Weaver LH, Matthews BW Proc Natl Acad Sci U S A. 1999 Aug 3;96(16):8949-54. PMID:10430876 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Lysozyme 3D structures

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