1X2T

Crystal Structure of Habu IX-bp at pH 6.5


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.72 Å
  • R-Value Free: 0.222 
  • R-Value Work: 0.191 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

pH-Dependent Structural Changes at Ca(2+)-binding sites of Coagulation Factor IX-binding Protein

Suzuki, N.Fujimoto, Z.Morita, T.Fukamizu, A.Mizuno, H.

(2005) J.Mol.Biol. 353: 80-87

  • DOI: 10.1016/j.jmb.2005.08.018
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Coagulation factor IX-binding protein, isolated from Trimeresurus flavoviridis (IX-bp), is a C-type lectin-like protein. It is an anticoagulant consisting of homologous subunits, A and B. Each subunit has a Ca(2+)-binding site with a unique affinity ...

    Coagulation factor IX-binding protein, isolated from Trimeresurus flavoviridis (IX-bp), is a C-type lectin-like protein. It is an anticoagulant consisting of homologous subunits, A and B. Each subunit has a Ca(2+)-binding site with a unique affinity (K(d) values of 14muM and 130muM at pH 7.5). These binding characteristics are pH-dependent and, under acidic conditions, the Ca(2+) binding of the low-affinity site was reduced considerably. In order to identify which site has high affinity and to investigate the pH-dependent Ca(2+) release mechanism, we have determined the crystal structures of IX-bp at pH 6.5 and pH 4.6 (apo form), and compared the Ca(2+)-binding sites with each other and with those of the solved structures under alkaline conditions; pH 7.8 and pH 8.0 (complexed form). At pH 6.5, Glu43 in the Ca(2+)-binding site of subunit A displayed two conformations. One (minor) is that in the alkaline state, and the other (major) is that at pH 4.6. However, the corresponding Gln43 residue of subunit B is in only a single conformation, which is almost identical with that in the alkaline state. At pH 4.6, Glu43 of subunit A adopts a conformation similar to that of the major conformer observed at pH 6.5, while Gln43 of subunit B assumes a new conformation, and both Ca(2+) positions are occupied by water molecules. These results showed that Glu43 of subunit A is much more sensitive to protonation than Gln43 of subunit B, and the conformational change of Glu43 occurs around pH6.5, which may correspond to the step of Ca(2+) release.


    Organizational Affiliation

    Department of Biochemistry, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Coagulation factor IX/X-binding protein A chain
A, C
129Protobothrops flavoviridisMutation(s): 0 
Find proteins for Q7LZ71 (Protobothrops flavoviridis)
Go to UniProtKB:  Q7LZ71
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Coagulation factor IX/factor X-binding protein B chain
B, D
123Protobothrops flavoviridisMutation(s): 0 
Find proteins for P23807 (Protobothrops flavoviridis)
Go to UniProtKB:  P23807
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
A, B, C, D
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
1PE
Query on 1PE

Download SDF File 
Download CCD File 
B, D
PENTAETHYLENE GLYCOL
PEG400
C10 H22 O6
JLFNLZLINWHATN-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.72 Å
  • R-Value Free: 0.222 
  • R-Value Work: 0.191 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 60.710α = 90.00
b = 63.509β = 117.00
c = 66.902γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
AMoREphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-10-04
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-10-11
    Type: Refinement description