title: In vitro hexagonal assembly of lipopolysaccharide of Escherichia coli K-12.
abstract: We examined Escherichia coli K-12 lipopolysaccharide (LPS), which is known to be an R-form LPS, for its ability to form a hexagonal lattice structure in vitro. The LPS from E. coli K-12 strain JE1011 did not form a hexagonal lattice structure when it was precipitated by addition of two volumes of 10 mM MgCl2-ethanol, but it did form such a structure when it was electrodialyzed and then converted to the magnesium or calcium salt form. The lattice constant of the magnesium salt form was 15.2 +/- 0.3 nm and that of the calcium salt form 18.5 +/- 0.3 nm. Since prior treatment of the LPS with proteinase K in the presence of sodium dodecyl sulfate did not affect its capability of hexagonal assembly, the lattice formation by the LPS does not require the presence of proteins.
mesh_terms: D002118:Calcium; D019286:Endopeptidase K; D010450:Endopeptidases / Q000378:metabolism; D004926:Escherichia coli / Q000032:analysis*; D008070:Lipopolysaccharides / Q000032:analysis*; D008274:Magnesium; D008854:Microscopy, Electron; D008968:Molecular Conformation; D012967:Sodium Dodecyl Sulfate
chemical_list: D008070:Lipopolysaccharides; D012967:Sodium Dodecyl Sulfate; D010450:Endopeptidases; D019286:Endopeptidase K; D008274:Magnesium; D002118:Calcium