1L99

PERTURBATION OF TRP 138 IN T4 LYSOZYME BY MUTATIONS AT GLN 105 USED TO CORRELATE CHANGES IN STRUCTURE, STABILITY, SOLVATION, AND SPECTROSCOPIC PROPERTIES


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Observed: 0.168 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Perturbation of Trp 138 in T4 lysozyme by mutations at Gln 105 used to correlate changes in structure, stability, solvation, and spectroscopic properties.

Pjura, P.McIntosh, L.P.Wozniak, J.A.Matthews, B.W.

(1993) Proteins 15: 401-412

  • DOI: https://doi.org/10.1002/prot.340150407
  • Primary Citation of Related Structures:  
    1L00, 1L98, 1L99

  • PubMed Abstract: 

    In order to correlate between spectroscopic and structural changes in a protein, the environment of Trp 135 in T4 lysozyme was deliberately perturbed by the replacement of Gln 105 with alanine (Q105A), glycine (Q105G), and glutamic acid (Q105E). In wild-type lysozyme, Trp 135 is buried, but the indole nitrogen is hydrogen-bonded to the side-chain of Gln 105. In the Q105G and Q105A mutant structures, the indole nitrogen becomes accessible to solvent. Crystallographic analysis shows that the structures of all of the mutants are similar to wild-type. There are, however, distinct rearrangements of the local solvent structure in response to the new side-chains. There are also small but significant changes in the relative orientations of the two domains of the protein that appear to result from a series of small, concerted movements of side-chains adjacent to residue 105. Evaluation of the fluorescence and phosphorescence of the mutant proteins in terms of their observed three-dimensional structures shows that large spectral changes do not necessarily imply large changes in structure or in static solvent accessibility. Increases in polar relaxation about the excited state of tryptophan may be the result of only small increases in local dynamics or solvent exposure. 1H-NMR was also used to monitor the effects of the substitutions on Trp 138. In Q105E, but not in Q105G, Q105A and WT, the H epsilon chemical shift of Trp 138 is very pH-dependent, apparently reflecting the titration of Glu 105 which has a spectroscopically determined pKa of 6.0. The elevation of the pKa of Glu 105 in Q105E is also reflected in the pH dependence of the stability of this mutant.


  • Organizational Affiliation

    Institute of Molecular Biology, University of Oregon, Eugene 97403.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
T4 LYSOZYME164Tequatrovirus T4Mutation(s): 0 
EC: 3.2.1.17
UniProt
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
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
BME
Query on BME

Download Ideal Coordinates CCD File 
B [auth A]BETA-MERCAPTOETHANOL
C2 H6 O S
DGVVWUTYPXICAM-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Observed: 0.168 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 61.2α = 90
b = 61.2β = 90
c = 95.6γ = 120
Software Package:
Software NamePurpose
TNTrefinement

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1993-10-31
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance