Open AccessThe Campylobacter jejuni Porin Trimers Pack into Different Lattice Types when Reconstituted in the Presence of Lipid
Author(s) -
Zhuang Jianping,
Engel Andreas,
Pagès JeanMarie,
Bolla JeanMichel
Publication year - 1997
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1997.t01-1-00575.x
Subject(s) - porin , campylobacter jejuni , negative stain , molecular mass , crystallography , bacterial outer membrane , monomer , membrane , electron microscope , escherichia coli , chemistry , materials science , bacteria , biology , biochemistry , polymer , genetics , physics , organic chemistry , optics , gene , enzyme
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°C [Bolla, J. M., Loret, E., Zalewski, M. & Pagès, J. M. (1995) J. Bacterial. 177 , 4266–4271]. The high‐molecular‐mass product was reconstituted into two‐dimensional crystals in the presence of phospholipids and Mg 2+ . 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, γ= 98°, 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.