Targeting a surface cavity of alpha 1-antitrypsin to prevent conformational disease

J Biol Chem. 2003 Aug 29;278(35):33060-6. doi: 10.1074/jbc.M302646200. Epub 2003 Jun 13.


Conformational diseases are caused by a structural rearrangement within a protein that results in aberrant intermolecular linkage and tissue deposition. This is typified by the polymers that form with the Z deficiency variant of alpha 1-antitrypsin (Glu-342 --> Lys). These polymers are retained within hepatocytes to form inclusions that are associated with hepatitis, cirrhosis, and hepatocellular carcinoma. We have assessed a surface hydrophobic cavity in alpha1-antitrypsin as a potential target for rational drug design in order to prevent polymer formation and the associated liver disease. The introduction of either Thr-114 --> Phe or Gly-117 --> Phe on strand 2 of beta-sheet A within this cavity significantly raised the melting temperature and retarded polymer formation. Conversely, Leu-100 --> Phe on helix D accelerated polymer formation, but this effect was abrogated by the addition of Thr-114 --> Phe. None of these mutations affected the inhibitory activity of alpha 1-antitrypsin. The importance of these observations was underscored by the finding that the Thr-114 --> Phe mutation reduced polymer formation and increased the secretion of Z alpha 1-antitrypsin from a Xenopus oocyte expression system. Moreover cysteine mutants within the hydrophobic pocket were able to bind a range of fluorophores illustrating the accessibility of the cavity to external agents. These results demonstrate the importance of this cavity as a site for drug design to ameliorate polymerization and prevent the associated conformational disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Carcinoma, Hepatocellular / metabolism
  • Chymotrypsin / chemistry
  • Crystallography, X-Ray
  • Cysteine / chemistry
  • Fibrosis / metabolism
  • Glycine / chemistry
  • Hepatitis / metabolism
  • Hepatocytes / metabolism
  • Hydrogen-Ion Concentration
  • Models, Molecular
  • Mutation
  • Oocytes / metabolism
  • Phenylalanine / chemistry
  • Polymers / chemistry
  • Potassium Chloride / chemistry
  • Protein Binding
  • Protein Conformation
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Recombinant Proteins / chemistry
  • Temperature
  • Threonine / chemistry
  • Time Factors
  • Xenopus
  • alpha 1-Antitrypsin / chemistry*
  • alpha 1-Antitrypsin / metabolism


  • Polymers
  • Recombinant Proteins
  • alpha 1-Antitrypsin
  • Threonine
  • Phenylalanine
  • Potassium Chloride
  • Chymotrypsin
  • alpha-chymotrypsin
  • Cysteine
  • Glycine