title: The Campylobacter jejuni porin trimers pack into different lattice types when reconstituted in the presence of lipid.
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.
authors.affiliation: M.E. Müller-Institute for Microscopic Structural Biology, Biozentrum of the University of Basel, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Zhuang
authors.forename: A
authors.initials: A
authors.lastname: Engel
authors.forename: J M
authors.initials: JM
authors.lastname: Pagés
authors.forename: J M
authors.initials: JM
authors.lastname: Bolla
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry; D016123:Campylobacter jejuni / Q000737:chemistry* / Q000648:ultrastructure; D003460:Crystallization; D003461:Crystallography; D004926:Escherichia coli / Q000737:chemistry; D008055:Lipids / Q000737:chemistry; D016253:Microscopy, Immunoelectron; D015394:Molecular Structure; D008970:Molecular Weight; D018272:Porins / Q000737:chemistry* / Q000302:isolation & purification; D011487:Protein Conformation
chemical_list: D001425:Bacterial Outer Membrane Proteins; D008055:Lipids; D018272:Porins