4EKQ

T4 Lysozyme L99A/M102H with 4-Nitrophenol Bound


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.54 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.175 
  • R-Value Observed: 0.176 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.4 of the entry. See complete history


Literature

Engineering a model protein cavity to catalyze the Kemp elimination.

Merski, M.Shoichet, B.K.

(2012) Proc Natl Acad Sci U S A 109: 16179-16183

  • DOI: https://doi.org/10.1073/pnas.1208076109
  • Primary Citation of Related Structures:  
    4E97, 4EKP, 4EKQ, 4EKR, 4EKS

  • PubMed Abstract: 

    Synthetic cavitands and protein cavities have been widely studied as models for ligand recognition. Here we investigate the Met102 → His substitution in the artificial L99A cavity in T4 lysozyme as a Kemp eliminase. The resulting enzyme had k(cat)/K(M) = 0.43 M(-1) s(-1) and a (k(cat)/K(M))/k(uncat) = 10(7) at pH 5.0. The crystal structure of this enzyme was determined at 1.30 Å, as were the structures of four complexes of substrate and product analogs. The absence of ordered waters or hydrogen bonding interactions, and the presence of a common catalytic base (His102) in an otherwise hydrophobic, buried cavity, facilitated detailed analysis of the reaction mechanism and its optimization. Subsequent substitutions increased eliminase activity by an additional four-fold. As activity-enhancing substitutions were engineered into the cavity, protein stability decreased, consistent with the stability-function trade-off hypothesis. This and related model cavities may provide templates for studying protein design principles in radically simplified environments.


  • Organizational Affiliation

    Department of Pharmaceutical Chemistry, University of California-San Francisco, San Francisco, CA 94158-2550, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Lysozyme
A, B
187Tequatrovirus T4Mutation(s): 8 
Gene Names: E
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 5 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
HED
Query on HED

Download Ideal Coordinates CCD File 
I [auth A]2-HYDROXYETHYL DISULFIDE
C4 H10 O2 S2
KYNFOMQIXZUKRK-UHFFFAOYSA-N
NPO
Query on NPO

Download Ideal Coordinates CCD File 
D [auth A],
E [auth A],
K [auth B]
P-NITROPHENOL
C6 H5 N O3
BTJIUGUIPKRLHP-UHFFFAOYSA-N
SO4
Query on SO4

Download Ideal Coordinates CCD File 
F [auth A],
G [auth A],
H [auth A],
L [auth B],
M [auth B]
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
BME
Query on BME

Download Ideal Coordinates CCD File 
C [auth A],
J [auth B]
BETA-MERCAPTOETHANOL
C2 H6 O S
DGVVWUTYPXICAM-UHFFFAOYSA-N
ACT
Query on ACT

Download Ideal Coordinates CCD File 
N [auth B]ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.54 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.175 
  • R-Value Observed: 0.176 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 48.21α = 90
b = 76.07β = 93.01
c = 52.81γ = 90
Software Package:
Software NamePurpose
XSCALEdata scaling
PHENIXrefinement
PDB_EXTRACTdata extraction
Blu-Icedata collection
XDSdata reduction
PHENIXphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-09-05
    Type: Initial release
  • Version 1.1: 2012-10-03
    Changes: Database references
  • Version 1.2: 2012-10-17
    Changes: Database references
  • Version 1.3: 2020-01-15
    Changes: Database references, Derived calculations
  • Version 1.4: 2023-09-13
    Changes: Data collection, Database references, Derived calculations, Refinement description