View the Current Issue

Article

  • The EMBO Journal (2001) 20, 6570 - 6582
  • doi:10.1093/emboj/20.23.6570

Structure of human dipeptidyl peptidase I (cathepsin C): exclusion domain added to an endopeptidase framework creates the machine for activation of granular serine proteases

Dus caronan Turk1, Vojko Janjic acute5, Igor S carontern1, Marjetka Podobnik2, Doriano Lamba3, Søren Weis Dahl4, Connie Lauritzen4, John Pedersen4, Vito Turk1 and Boris Turk1

  1. Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
  2. Present address: Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10021-6399, USA
  3. International Centre for Genetic Engineering and Biotechnology, Area Science Park, Padriciano 99, I-34012 Trieste, Italy
  4. Unizyme Laboratories A/S, Dr Neergaards vej 17, DK-2970 Hoersholm, Denmark
  5. Deceased

Correspondence to:

Dus caronan Turk, E-mail: Dusan.Turk@ijs.si

Received 5 July 2001; Accepted 8 October 2001; Revised 3 October 2001

Dipeptidyl peptidase I (DPPI) or cathepsin C is the physiological activator of groups of serine proteases from immune and inflammatory cells vital for defense of an organism. The structure presented shows how an additional domain transforms the framework of a papain-like endopeptidase into a robust oligomeric protease-processing enzyme. The tetrahedral arrangement of the active sites exposed to solvent allows approach of proteins in their native state; the massive body of the exclusion domain fastened within the tetrahedral framework excludes approach of a polypeptide chain apart from its termini; and the carboxylic group of Asp1 positions the N-terminal amino group of the substrate. Based on a structural comparison and interactions within the active site cleft, it is suggested that the exclusion domain originates from a metallo-protease inhibitor. The location of missense mutations, characterized in people suffering from Haim–Munk and Papillon–Lefevre syndromes, suggests how they disrupt the fold and function of the enzyme.

  • Keywords:

    • apoptosis,
    • cysteine protease,
    • granzyme,
    • inflammation,
    • zymogen activation