1TCY

DISSECTION OF THE FUNCTIONAL ROLE OF STRUCTURAL ELEMENTS OF TYROSINE-63 IN THE CATALYTIC ACTION OF HUMAN LYSOZYME


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Work: 0.182 
  • R-Value Observed: 0.182 

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This is version 1.3 of the entry. See complete history


Literature

Dissection of the functional role of structural elements of tyrosine-63 in the catalytic action of human lysozyme.

Muraki, M.Harata, K.Jigami, Y.

(1992) Biochemistry 31: 9212-9219

  • DOI: 10.1021/bi00153a014
  • Primary Citation of Related Structures:  
    1TAY, 1TBY, 1TCY, 1TDY

  • PubMed Abstract: 
  • The functional role of tyrosine-63 in the catalytic action of human lysozyme (EC 3.2.1.17) has been probed by site-directed mutagenesis. In order to identify the role of Tyr63 in the interaction with substrate, both the three-dimensional structures a ...

    The functional role of tyrosine-63 in the catalytic action of human lysozyme (EC 3.2.1.17) has been probed by site-directed mutagenesis. In order to identify the role of Tyr63 in the interaction with substrate, both the three-dimensional structures and the enzymatic functions of the mutants, in which Tyr63 was converted to phenylalanine, tryptophan, leucine, or alanine, have been characterized in comparison with those of the wild-type enzyme. X-ray crystallographical analysis of the mutant enzyme at not less than 1.77-A resolution indicated no remarkable change in tertiary structure except the side chain of 63rd residue. The conversion of Tyr63 to Phe or Trp did not change the enzymatic properties against the noncharged substrate (or substrate analogs) largely, while the conversion to Leu or Ala markedly reduced the catalytic activity to a few percent of wild-type enzyme. Kinetic analysis using p-nitrophenyl penta-N-acetyl-beta-(1----4)-chitopentaoside (PNP-(GlcNAc)5) as a substrate revealed that the reduction of activity should mainly be attributed to the reduction of affinity between enzyme and substrate. The apparent contribution of the phenolic hydroxyl group and the phenol group in the side chain of Tyr63 was estimated to 0.4 +/- 0.4 and 2.5 +/- 0.8 kcal mol-1, respectively. The result suggested that the direct contact between the planar side-chain group of Tyr63 and the sugar residue at subsite B is a major determinant of binding specificity toward a electrostatically neutral substrate in the catalytic action of human lysozyme.


    Organizational Affiliation

    Biological Chemistry Division, National Chemical Laboratory for Industry, Ibaraki, Japan.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
HUMAN LYSOZYMEA130Homo sapiensMutation(s): 0 
Gene Names: LYZLZM
EC: 3.2.1.17
Find proteins for P61626 (Homo sapiens)
Explore P61626 
Go to UniProtKB:  P61626
NIH Common Fund Data Resources
PHAROS  P61626
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Work: 0.182 
  • R-Value Observed: 0.182 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 57.19α = 90
b = 60.98β = 90
c = 33.02γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1993-01-15
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-11-29
    Changes: Derived calculations, Other