3EHI

Crystal Structure of Human Thymidyalte Synthase M190K with Loop 181-197 stabilized in the inactive conformation


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.198 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Variants of human thymidylate synthase with loop 181-197 stabilized in the inactive conformation.

Lovelace, L.L.Johnson, S.R.Gibson, L.M.Bell, B.J.Berger, S.H.Lebioda, L.

(2009) Protein Sci. 18: 1628-1636

  • DOI: 10.1002/pro.171
  • Primary Citation of Related Structures:  3EGY

  • PubMed Abstract: 
  • Loop 181-197 of human thymidylate synthase (hTS) populates two major conformations, essentially corresponding to the loop flipped by 180 degrees . In one of the conformations, the catalytic Cys195 residue lies distant from the active site making the ...

    Loop 181-197 of human thymidylate synthase (hTS) populates two major conformations, essentially corresponding to the loop flipped by 180 degrees . In one of the conformations, the catalytic Cys195 residue lies distant from the active site making the enzyme inactive. Ligands stabilizing this inactive conformation may function as allosteric inhibitors. To facilitate the search for such inhibitors, we have expressed and characterized several mutants designed to shift the equilibrium toward the inactive conformer. In most cases, the catalytic efficiency of the mutants was only somewhat impaired with values of k(cat)/K(m) reduced by factors in a 2-12 range. One of the mutants, M190K, is however unique in having the value of k(cat)/K(m) smaller by a factor of approximately 7500 than the wild type. The crystal structure of this mutant is similar to that of the wt hTS with loop 181-197 in the inactive conformation. However, the direct vicinity of the mutation, residues 188-194 of this loop, assumes a different conformation with the positions of C(alpha) shifted up to 7.2 A. This affects region 116-128, which became ordered in M190K while it is disordered in wt. The conformation of 116-128 is however different than that observed in hTS in the active conformation. The side chain of Lys190 does not form contacts and is in solvent region. The very low activity of M190K as compared to another mutant with a charged residue in this position, M190E, suggests that the protein is trapped in an inactive state that does not equilibrate easily with the active conformer.


    Organizational Affiliation

    Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Thymidylate synthase
X
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
SO4
Query on SO4

Download SDF File 
Download CCD File 
X
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
EDO
Query on EDO

Download SDF File 
Download CCD File 
X
1,2-ETHANEDIOL
ETHYLENE GLYCOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
CME
Query on CME
X
L-PEPTIDE LINKINGC5 H11 N O3 S2CYS
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.198 
  • Space Group: P 31 2 1
Unit Cell:
Length (Å)Angle (°)
a = 96.053α = 90.00
b = 96.053β = 90.00
c = 80.064γ = 120.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
SERGUIdata collection
REFMACrefinement
DENZOdata reduction
CNSphasing
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2009-08-18
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Advisory, Version format compliance
  • Version 1.2: 2017-10-25
    Type: Refinement description