Three-dimensional structure of the alkaline protease of Pseudomonas aeruginosa: a two-domain protein with a calcium binding parallel beta roll motif

EMBO J. 1993 Sep;12(9):3357-64.


The three-dimensional structure of the alkaline protease of Pseudomonas aeruginosa, a zinc metalloprotease, has been solved to a resolution of 1.64 A by multiple isomorphous replacement and non-crystallographic symmetry averaging between different crystal forms. The molecule is elongated with overall dimensions of 90 x 35 x 25 A; it has two distinct structural domains. The N-terminal domain is the proteolytic domain; it has an overall tertiary fold and active site zinc ligation similar to that of astacin, a metalloprotease isolated from a European freshwater crayfish. The C-terminal domain consists of a 21-strand beta sandwich. Within this domain is a novel 'parallel beta roll' structure in which successive beta strands are wound in a right-handed spiral, and in which Ca2+ ions are bound within the turns between strands by a repeated GGXGXD sequence motif, a motif that is found in a diverse group of proteins secreted by Gram-negative bacteria.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Astacoidea
  • Binding Sites
  • Calcium / metabolism
  • Consensus Sequence
  • Metalloendopeptidases / chemistry*
  • Metalloendopeptidases / metabolism
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation*
  • Protein Structure, Secondary*
  • Pseudomonas aeruginosa / enzymology*
  • Sequence Homology, Amino Acid
  • Zinc / metabolism


  • Metalloendopeptidases
  • astacin
  • Zinc
  • Calcium