The 1.5 Å Crystal Structure of a Prokaryote Serpin Academic Article uri icon


  • Serpins utilize conformational change to inhibit target proteinases; the price paid for this conformational flexibility is that many undergo temperature-induced polymerization. Despite this thermolability, serpins are present in the genomes of thermophilic prokaryotes, and here we characterize the first such serpin, thermopin. Thermopin is a proteinase inhibitor and, in comparison with human alpha(1)-antitrypsin, possesses enhanced stability at 60 degrees C. The 1.5 A crystal structure reveals novel structural features in regions implicated in serpin folding and stability. Thermopin possesses a C-terminal "tail" that interacts with the top of the A beta sheet and plays an important role in the folding/unfolding of the molecule. These data provide evidence as to how this unusual serpin has adapted to fold and function in a heated environment.


  • Irving, James A
  • Cabrita, Lisa D
  • Rossjohn, Jamie
  • Pike, Robert N
  • Bottomley, Stephen P
  • Whisstock, James C

publication date

  • April 2003