title: Disintegration of Mg2+ -induced hexagonal assembly of an R-form lipopolysaccharide from Klebsiella pneumoniae by treatment with CaCl2.
abstract: R-form lipopolysaccharide (LPS) from Klebsiella pneumoniae strain LEN-111 (O3-: K1-), which was precipitated by the addition of 2 volumes of ethanol containing 10 mM MgCl2 for the purification process, ultrastructurally exhibited membrane pieces consisting of an ordered hexagonal lattice structure with a lattice constant of 14 to 15 nm. When the R-form LPS was suspended in 50 mM tris (hydroxymethyl) aminomethane buffer (at pH 8.5) containing 1 mM or higher concentrations of CaCl2 and kept at 4 C for 10 hr, the ordered hexagonal lattice structure of the R-form LPS was disintegrated and changed to an irregular rough, mesh-like structure. By treatment with CaCl2, the content of Mg in the LPS was markedly decreased, and conversely, the content of Ca was increased to a level depending upon the concentration of CaCl2. Results indicate that the addition of CaCl2 to suspensions of the Mg-bound R-form LPS result in a tighter binding of Ca2+ to the R-form LPS and the release of Mg2+ from the R-form LPS, and as a consequence, destroys the Mg2+ -induced ordered hexagonal lattice structure of the R-form LPS.
authors.affiliation: Nagoya University School of Health Sciences, Aichi, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ito
authors.forename: S
authors.initials: S
authors.lastname: Naito
authors.forename: N
authors.initials: N
authors.lastname: Kato
mesh_terms: D002122:Calcium Chloride / Q000494:pharmacology*; D007711:Klebsiella pneumoniae / Q000378:metabolism* / Q000648:ultrastructure; D008070:Lipopolysaccharides / Q000378:metabolism* / Q000648:ultrastructure; D008274:Magnesium / Q000494:pharmacology*; D008854:Microscopy, Electron
chemical_list: D008070:Lipopolysaccharides; D008274:Magnesium; D002122:Calcium Chloride