1HXE

SERINE PROTEASE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Work: 0.151 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The molecular environment of the Na+ binding site of thrombin.

Zhang, E.Tulinsky, A.

(1997) Biophys.Chem. 63: 185-200

  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • When Na+ binds to thrombin, a conformational change is induced that renders the enzyme kinetically faster and more specific in the activation of fibrinogen. Two Na+ binding sites have here been identified crystallographically by exchanging Na+ with R ...

    When Na+ binds to thrombin, a conformational change is induced that renders the enzyme kinetically faster and more specific in the activation of fibrinogen. Two Na+ binding sites have here been identified crystallographically by exchanging Na+ with Rb+. One is intermolecular, found on the surface between two symmetry-related thrombin molecules. Since it is not present in thrombin crystal structures having different crystal systems, the other Na+ site is the functionally relevant one. The second site has octahedral coordination with the carbonyl oxygen atoms of Arg221A and Lys224 and four conserved water molecules. It is located near Asp189 of the S1 specificity site in an elongated solvent channel (8 x 18 A) formed by four antiparallel beta-strands between Cys182-Cys191 and Val213-Tyr228. This channel, extending from the active site to the opposite surface of the enzyme, was first noted in the hirudin-thrombin structure and contains about 20 conserved water molecules linked together by a hydrogen bonding network that connects to the main chain of thrombin. Although the antiparallel beta-strand interactions of the functional Na+ binding site are the same in prethrombin2, the loops between the strands are very different, so that Asp189 and Arg221A are not positioned properly for either substrate or Na+ binding in prethrombin2. A water molecule with octahedral coordination has also been identified in factor Xa at the topologically equivalent Na+ site position of thrombin. Since activated protein C shows enhanced activity with monovalant cation binding, the same position is probably utilized by Na+. Since thrombin crystals could not be grown in the absence of Na+, the cation was leached from Na(+)-bound thrombin crystals by diffusion/exchange. Although both Na+ and their coordinating water molecules were removed from the Na+ binding sites, the remainder of the thrombin structure was, unexpectedly, the same. The lack of an allosteric change is most likely attributable to crystal packing effects. Thus, the structure of the slow form remains to be established crystallographically.


    Related Citations: 
    • The Na+ Binding Site of Thrombin
      Di Cera, E.,Guinto, E.R.,Vindigni, A.,Dang, Q.D.,Ayala, Y.M.,Wuyi, M.,Tulinsky, A.
      (1995) J.Biol.Chem. 270: 22089
    • Refined Structure of the Hirudin-Thrombin Complex
      Rydel, T.J.,Tulinsky, A.,Bode, W.,Huber, R.
      (1991) J.Mol.Biol. 221: 583


    Organizational Affiliation

    Department of Chemistry, Michigan State University, East Lansing 48824, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
THROMBIN
L
36Homo sapiensMutation(s): 0 
Gene Names: F2
EC: 3.4.21.5
Find proteins for P00734 (Homo sapiens)
Go to Gene View: F2
Go to UniProtKB:  P00734
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
THROMBIN
H
259Homo sapiensMutation(s): 0 
Gene Names: F2
EC: 3.4.21.5
Find proteins for P00734 (Homo sapiens)
Go to Gene View: F2
Go to UniProtKB:  P00734
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
HIRUDIN VARIANT-1
I
10Hirudo medicinalisMutation(s): 0 
Find proteins for P01050 (Hirudo medicinalis)
Go to UniProtKB:  P01050
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
RB
Query on RB

Download SDF File 
Download CCD File 
H
RUBIDIUM ION
Rb
NCCSSGKUIKYAJD-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Work: 0.151 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 71.500α = 90.00
b = 72.300β = 101.00
c = 73.300γ = 90.00
Software Package:
Software NamePurpose
PROFFTrefinement
RAXISIIdata collection
R-AXISdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1996-11-08
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Atomic model, Database references, Derived calculations, Non-polymer description, Structure summary, Version format compliance