2RD8

Human Thymidylate Synthase Stabilized in Active Conformation by R163K Mutation: Asymmetry and Reactivity of Cys195


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.271 
  • R-Value Work: 0.228 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The R163K Mutant of Human Thymidylate Synthase Is Stabilized in an Active Conformation: Structural Asymmetry and Reactivity of Cysteine 195.

Gibson, L.M.Lovelace, L.L.Lebioda, L.

(2008) Biochemistry 47: 4636-4643

  • DOI: 10.1021/bi7019386
  • Primary Citation of Related Structures:  2RDA

  • PubMed Abstract: 
  • Loop 181-197 of human thymidylate synthase (hTS) populates two conformational states. In the first state, Cys195, a residue crucial for catalytic activity, is in the active site (active conformer); in the other conformation, it is about 10 A away, ou ...

    Loop 181-197 of human thymidylate synthase (hTS) populates two conformational states. In the first state, Cys195, a residue crucial for catalytic activity, is in the active site (active conformer); in the other conformation, it is about 10 A away, outside the active site (inactive conformer). We have designed and expressed an hTS variant, R163K, in which the inactive conformation is destabilized. The activity of this mutant is 33% higher than that of wt hTS, suggesting that at least one-third of hTS populates the inactive conformer. Crystal structures of R163K in two different crystal forms, with six and two subunits per asymmetric part of the unit cells, have been determined. All subunits of this mutant are in the active conformation while wt hTS crystallizes as the inactive conformer in similar mother liquors. The structures show differences in the environment of catalytic Cys195, which correlate with Cys195 thiol reactivity, as judged by its oxidation state. Calculations show that the molecular electrostatic potential at Cys195 differs between the subunits of the dimer. One of the dimers is asymmetric with a phosphate ion bound in only one of the subunits. In the absence of the phosphate ion, that is in the inhibitor-free enzyme, the tip of loop 47-53 is about 11 A away from the active site.


    Organizational Affiliation

    Department of Chemistry and Biochemistry and Center for Colon Cancer Research, University of South Carolina, Columbia, SC 29208, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Thymidylate synthase
A
313Homo sapiensGene Names: TYMS (TS)
EC: 2.1.1.45
Find proteins for P04818 (Homo sapiens)
Go to Gene View: TYMS
Go to UniProtKB:  P04818
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Thymidylate synthase
B
313Homo sapiensGene Names: TYMS (TS)
EC: 2.1.1.45
Find proteins for P04818 (Homo sapiens)
Go to Gene View: TYMS
Go to UniProtKB:  P04818
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PO4
Query on PO4

Download SDF File 
Download CCD File 
B
PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
BME
Query on BME

Download SDF File 
Download CCD File 
A
BETA-MERCAPTOETHANOL
C2 H6 O S
DGVVWUTYPXICAM-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
CME
Query on CME
B
L-PEPTIDE LINKINGC5 H11 N O3 S2CYS
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.271 
  • R-Value Work: 0.228 
  • Space Group: P 32 2 1
Unit Cell:
Length (Å)Angle (°)
a = 120.741α = 90.00
b = 120.741β = 90.00
c = 129.771γ = 120.00
Software Package:
Software NamePurpose
AMoREphasing
HKL-2000data collection
HKL-2000data reduction
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-05-27
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2017-10-25
    Type: Refinement description