Engineering outer-membrane proteins in Pseudomonas putida for enhanced heavy-metal bioadsorption

J Inorg Biochem. 2000 Apr;79(1-4):219-23. doi: 10.1016/s0162-0134(99)00170-1.


Metallothioneins (MTs) are small, cysteine-rich proteins with a strong metal-binding capacity that are ubiquitous in the animal kingdom. Recombinant expression of MT fused to outer-membrane components of gram-negative bacteria may provide new methods to treat heavy-metal pollution in industrial sewage. In this work, we have engineered Pseudomonas putida, a per se highly robust microorganism able to grow in highly contaminated habitats in order to further increase its metal-chelating ability. We report the expression of a hybrid protein between mouse MT and the beta domain of the IgA protease of Neisseria in the outer membrane of Pseudomonas cells. The metal-binding capacity of such cells was increased three-fold. The autotranslocating capacity of the beta domain of the IgA protease of Neisseria, as well as the correct anchoring of the transported protein into the outer membrane, have been demonstrated for the first time in a member of the Pseudomonas genus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption
  • Animals
  • Bacterial Outer Membrane Proteins / genetics
  • Bacterial Outer Membrane Proteins / metabolism*
  • Cadmium / metabolism*
  • DNA Transposable Elements
  • Environmental Pollutants / pharmacokinetics*
  • Metallothionein / genetics
  • Metallothionein / metabolism*
  • Metals, Heavy / pharmacokinetics*
  • Mice
  • Neisseria / enzymology
  • Pseudomonas putida / genetics
  • Pseudomonas putida / metabolism*
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / metabolism
  • Serine Endopeptidases / chemistry
  • Serine Endopeptidases / metabolism


  • Bacterial Outer Membrane Proteins
  • DNA Transposable Elements
  • Environmental Pollutants
  • Metals, Heavy
  • Recombinant Fusion Proteins
  • Cadmium
  • Metallothionein
  • Serine Endopeptidases
  • IgA-specific serine endopeptidase