T26H Mutant of T4 Lysozyme

Experimental Data Snapshot

  • Resolution: 1.90 Å
  • R-Value Observed: 0.169 

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Structural basis of the conversion of T4 lysozyme into a transglycosidase by reengineering the active site.

Kuroki, R.Weaver, L.H.Matthews, B.W.

(1999) Proc Natl Acad Sci U S A 96: 8949-8954

  • DOI: https://doi.org/10.1073/pnas.96.16.8949
  • Primary Citation of Related Structures:  
    1QT3, 1QT4, 1QT5, 1QT6, 1QT7, 1QT8, 1QTV, 1QTZ

  • PubMed Abstract: 

    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.

  • Organizational Affiliation

    Central Laboratories for Key Technology, Kirin Brewery Co., Ltd., 1-13-5, Fukuura, Kanazawa-ku, Yokohama 236 Japan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
PROTEIN (T4 LYSOZYME)164Tequatrovirus T4Mutation(s): 3 
Find proteins for P00720 (Enterobacteria phage T4)
Explore P00720 
Go to UniProtKB:  P00720
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00720
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on HED

Download Ideal Coordinates CCD File 
C4 H10 O2 S2
Experimental Data & Validation

Experimental Data

  • Resolution: 1.90 Å
  • R-Value Observed: 0.169 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 61.451α = 90
b = 61.451β = 90
c = 97.679γ = 120
Software Package:
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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1999-07-08
    Type: Initial release
  • Version 1.1: 2007-10-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-11-03
    Changes: Database references, Derived calculations
  • Version 1.4: 2024-02-14
    Changes: Data collection