1qt5
From Proteopedia
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| - | [[Image:1qt5.jpg|left|200px]] | + | [[Image:1qt5.jpg|left|200px]] |
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| - | '''D20E MUTANT STRUCTURE OF T4 LYSOZYME''' | + | {{Structure |
| + | |PDB= 1qt5 |SIZE=350|CAPTION= <scene name='initialview01'>1qt5</scene>, resolution 1.8Å | ||
| + | |SITE= | ||
| + | |LIGAND= <scene name='pdbligand=HED:2-HYDROXYETHYL DISULFIDE'>HED</scene> | ||
| + | |ACTIVITY= [http://en.wikipedia.org/wiki/Lysozyme Lysozyme], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.17 3.2.1.17] | ||
| + | |GENE= | ||
| + | }} | ||
| + | |||
| + | '''D20E MUTANT STRUCTURE OF T4 LYSOZYME''' | ||
| + | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1QT5 is a [ | + | 1QT5 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_t4 Bacteriophage t4]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QT5 OCA]. |
==Reference== | ==Reference== | ||
| - | 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:[http:// | + | 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:[http://www.ncbi.nlm.nih.gov/pubmed/10430876 10430876] |
[[Category: Bacteriophage t4]] | [[Category: Bacteriophage t4]] | ||
[[Category: Lysozyme]] | [[Category: Lysozyme]] | ||
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[[Category: hydrolase]] | [[Category: hydrolase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 13:42:21 2008'' |
Revision as of 11:42, 20 March 2008
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| , resolution 1.8Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | |||||||
| Activity: | Lysozyme, with EC number 3.2.1.17 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
D20E MUTANT STRUCTURE OF T4 LYSOZYME
Overview
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.
About this Structure
1QT5 is a Single protein structure of sequence from Bacteriophage t4. Full crystallographic information is available from OCA.
Reference
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
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