The NMR structure of the activation domain isolated from porcine procarboxypeptidase B

EMBO J. 1991 Jan;10(1):11-5.


The three-dimensional structure of the activation domain isolated from porcine pancreatic procarboxypeptidase B was determined using 1H NMR spectroscopy. A group of 20 conformers is used to describe the solution structure of this 81 residue polypeptide chain, which has a well-defined backbone fold from residues 11-76 with an average root mean square distance for the backbone atoms of 1.0 +/- 0.1 A relative to the mean of the 20 conformers. The molecular architecture contains a four-stranded beta-sheet with the polypeptide segments 11-17, 36-39, 50-56 and 75-76, two well defined alpha-helices from residues 20-30 and 60-70, and a 3(10) helix from residues 43-46. The three helices are oriented almost exactly antiparallel to each other, are all on the same side of the beta-sheet, and the helix axes from an angle of approximately 45 degrees relative to the direction of the beta-strands. Three segments linking beta-strands and helical secondary structures, with residues 32-35, 39-43 and 56-61, are significantly less well ordered than the rest of the molecule. In the three-dimensional structure two of these loops (residues 32-35 and 56-61) are located close to each other near the protein surface, forming a continuous region of increased mobility, and the third disordered loop is separated from this region only by the peripheral beta-strand 36-39 and precedes the short 3(10) helix.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Carboxypeptidase B
  • Carboxypeptidases / chemistry*
  • Carboxypeptidases / metabolism
  • Enzyme Activation
  • Enzyme Precursors / chemistry*
  • Enzyme Precursors / metabolism
  • Magnetic Resonance Spectroscopy / methods
  • Models, Molecular
  • Molecular Sequence Data
  • Pancreas / enzymology
  • Protein Conformation
  • Swine


  • Enzyme Precursors
  • Carboxypeptidases
  • Carboxypeptidase B