1T1F

Crystal Structure of Native Antithrombin in its Monomeric Form


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.75 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.225 

wwPDB Validation 3D Report Full Report



Literature

Crystal structure of monomeric native antithrombin reveals a novel reactive center loop conformation

Johnson, D.J.D.Langdown, J.Li, W.Luis, S.A.Baglin, T.P.Huntington, J.A.

(2006) J Biol Chem 281: 35478-35486

  • DOI: 10.1074/jbc.M607204200
  • Primary Citation of Related Structures:  
    2B5T, 2BEH, 1T1F

  • PubMed Abstract: 
  • The poor inhibitory activity of circulating antithrombin (AT) is critical to the formation of blood clots at sites of vascular damage. AT becomes an efficient inhibitor of the coagulation proteases only after binding to a specific heparin pentasaccha ...

    The poor inhibitory activity of circulating antithrombin (AT) is critical to the formation of blood clots at sites of vascular damage. AT becomes an efficient inhibitor of the coagulation proteases only after binding to a specific heparin pentasaccharide, which alters the conformation of the reactive center loop (RCL). The molecular basis of this activation event lies at the heart of the regulation of hemostasis and accounts for the anticoagulant properties of the low molecular weight heparins. Although several structures of AT have been solved, the conformation of the RCL in native AT remains unknown because of the obligate crystal contact between the RCL of native AT and its latent counterpart. Here we report the crystallographic structure of a variant of AT in its monomeric native state. The RCL shifted approximately 20 A, and a salt bridge was observed between the P1 residue (Arg-393) and Glu-237. This contact explains the effect of mutations at the P1 position on the affinity of AT for heparin and also the properties of AT-Truro (E237K). The relevance of the observed conformation was verified through mutagenesis studies and by solving structures of the same variant in different crystal forms. We conclude that the poor inhibitory activity of the circulating form of AT is partially conferred by intramolecular contacts that restrain the RCL, orient the P1 residue away from attacking proteases, and additionally block the exosite utilized in protease recognition.


    Organizational Affiliation

    Department of Haematology, Division of Structural Medicine, Thrombosis Research Unit, Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 2XY, United Kingdom.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Antithrombin-IIIABC432Homo sapiensMutation(s): 3 
Gene Names: SERPINC1AT3PRO0309
Find proteins for P01008 (Homo sapiens)
Explore P01008 
Go to UniProtKB:  P01008
NIH Common Fund Data Resources
PHAROS  P01008
Protein Feature View
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  • Reference Sequence
Oligosaccharides

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Entity ID: 2
MoleculeChainsChain Length2D Diagram Glycosylation
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
D, F, G, I, J, L
2 N-Glycosylation
Entity ID: 3
MoleculeChainsChain Length2D Diagram Glycosylation
beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
E, H, K
3 N-Glycosylation
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
IOD
Query on IOD

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A, B, C
IODIDE ION
I
XMBWDFGMSWQBCA-UHFFFAOYSA-M
 Ligand Interaction
GOL
Query on GOL

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A, B, C
GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.75 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.225 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 153.83α = 90
b = 43.71β = 120.01
c = 153.93γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling
MOLREPphasing
CNSrefinement
CCP4data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-10-04
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary