Gene Structure and Extracellular Secretion of Neisseria Gonorrhoeae IgA Protease

Nature. 1987 Jan 29-Feb 4;325(6103):458-62. doi: 10.1038/325458a0.

Abstract

Several human bacterial pathogens, including the Gram-negative diplococcus Neisseria gonorrhoeae, produce extracellular proteases that are specific for human immunoglobulin IgA1. Immunoglobulin A (IgA) proteases have been studied extensively and the genes of some species cloned in Escherichia coli, but their role in pathogenesis remains unclear. Recently we derived a DNA fragment of 5 kilobases (kb) from N. gonorrhoeae MS11 directing extracellular active enzyme in E. coli. Although the mature enzyme of strain MS11 was shown to have a relative molecular mass of 106,000 (Mr 106K) in gels, the DNA sequence of this cloned fragment reveals a single gene coding for a 169K precursor of IgA protease. The precursor contains three functional domains, the amino-terminal leader which is assumed to initiate the inner membrane transport of the precursor, the protease, and a carboxyl-terminal 'helper' domain apparently required for extracellular secretion (excretion). Based on the structural features of the precursor, we propose a model in which the helper serves as a pore for excretion of the protease domain through the outer membrane. IgA protease acquires an active conformation as its extracellular transport proceeds and is released as a proform from the membrane-bound helper by autoproteolysis. The soluble proform further matures into the 106 K IgA protease and a small stable alpha-protein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • DNA Restriction Enzymes
  • Escherichia coli / genetics
  • Genes*
  • Genes, Bacterial*
  • Neisseria gonorrhoeae / enzymology*
  • Neisseria gonorrhoeae / genetics
  • Peptide Hydrolases / genetics*
  • Peptide Hydrolases / metabolism
  • Protein Conformation
  • Serine Endopeptidases*

Substances

  • DNA Restriction Enzymes
  • Peptide Hydrolases
  • Serine Endopeptidases
  • IgA-specific serine endopeptidase

Associated data

  • GENBANK/X04835