Thromboembolic disease due to thermolabile conformational changes of antithrombin Rouen-VI (187 Asn-->Asp)

J Clin Invest. 1994 Dec;94(6):2265-74. doi: 10.1172/JCI117589.


A new variant of antithrombin (Rouen-VI, 187 Asn-->Asp) with increased heparin affinity was shown to have normal inhibitory activity which decreased slowly at 4 degrees C and rapidly at 41 degrees C. On electrophoresis the freshly isolated variant had an anodal shift relative to native antithrombin due to the mutation. A further anodal transition occurred after either prolonged storage at 4 degrees C or incubation at 41 degrees C due to the formation of a new inactive uncleaved component with properties characteristic of L-form (latent) antithrombin. At the same time, polymerization also occurred with a predominance of di-, tri-, and tetra-mers. These findings fit with the observed mutation of the conserved asparagine (187) in the F-helix destabilizing the underlying A-sheet of the molecule. Evidence of A-sheet perturbation is provided by the increased rate of peptide insertion into the A-sheet and by the decreased vulnerability of the reactive loop to proteolysis. The spontaneous formation of both L-antithrombin and polymers is consistent with our crystal structure of intact antithrombin where L-form and active antithrombin are linked together as dimers. The nature of this linkage favors a mechanism of polymerization whereby the opening of the A-sheet, to give incorporation of the reactive center loop, is accompanied by the bonding of the loop of one molecule to the C-sheet of the next. The accelerated lability of antithrombin Rouen-VI at 41 versus 37 degrees C provides an explanation for the clinical observation that episodes of thrombosis were preceded by unrelated pyrexias.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Amino Acid Sequence
  • Antithrombin Proteins
  • Antithrombins / chemistry
  • Antithrombins / genetics*
  • Antithrombins / ultrastructure
  • Female
  • Fever / complications
  • Hot Temperature
  • Humans
  • Models, Molecular
  • Molecular Sequence Data
  • Point Mutation*
  • Polymerase Chain Reaction
  • Pregnancy
  • Pregnancy Complications, Cardiovascular / etiology
  • Protein Structure, Tertiary*
  • Sequence Analysis, DNA
  • Structure-Activity Relationship
  • Thrombin / metabolism
  • Thrombophlebitis / etiology
  • Thrombophlebitis / genetics*


  • Antithrombin Proteins
  • Antithrombins
  • antithrombin Rouen-VI
  • Thrombin