The Campylobacter jejuni porin trimers pack into different lattice types when reconstituted in the presence of lipid

Eur J Biochem. 1997 Mar 1;244(2):575-9. doi: 10.1111/j.1432-1033.1997.t01-1-00575.x.

Abstract

Purified major outer membrane protein of Campylobacter jejuni exhibited different classes of molecules by SDS/PAGE and immunoblotting. A high-molecular-mass product (120-140 kDa) was observed under mild conditions of solubilization, a folded monomeric form of 35 kDa was seen when treated at high SDS concentrations and finally, a single band around 45 kDa occurred when the sample was heated to 96 degrees C [Bolla, J. M., Loret, E., Zalewski. M. & Pages, J. M. (1995) J. Bacteriol. 177, 4266-4271]. The high-molecular-mass product was reconstituted into two-dimensional crystals in the presence of phospholipids and Mg2+. The C. jejuni porin required different conditions for successful reconstitution into two-dimensional crystals than the Escherichia coli porin OmpF. Electron microscopy and digital image processing of negatively stained specimens revealed a rectangular lattice with a unit cells size of a = 8.9 nm, b = 14.9 nm, an oblique lattice with a = 8.9 nm, b = 30.1 nm, gamma = 98 degrees, and a trigonal lattice with a = b = 9.6 nm. Projection maps were calculated to a resolution of 2 nm, and exhibited a trimeric protein with three stain-filled indentations.

Publication types

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

MeSH terms

  • Bacterial Outer Membrane Proteins / chemistry
  • Campylobacter jejuni / chemistry*
  • Campylobacter jejuni / ultrastructure
  • Crystallization
  • Crystallography
  • Escherichia coli / chemistry
  • Lipids / chemistry
  • Microscopy, Immunoelectron
  • Molecular Structure
  • Molecular Weight
  • Porins / chemistry*
  • Porins / isolation & purification
  • Protein Conformation

Substances

  • Bacterial Outer Membrane Proteins
  • Lipids
  • Porins