[Binding of porin with lipopolysaccharide from Yersinia pseudotuberculosis]. / Sviazyvanie porina s lipopolisakharidom iz Yersinia pseudotuberculosis.

Interactions, of porin a protein from Yersinia pseudotuberculosis, with S- and R-LPS and lipid A were investigated by means of fluorescence and CD-spectroscopy, differential scanning microcalorimetry and CsCl gradient ultracentrifugation. S-LPS--porin monomer stoichiometry was shown by fluorescence titration to be 6:1. Ultracentrifugation data suggest that the maximum number of LPS molecules bound per porin monomer in three. Two equivalent lipid A binding sites on porin were determined, data the associated binding constant being 6.1 x 10(4) M-1. Interactions between S- and R-LPS and porin monomer were shown to by positive and negative cooperativity, respectively. The data suggest an important role of the structural moieties of LPS molecule in the binding process. On the basis of these results and the structure of ligands a mechanism of LPS-porin interaction is discussed.

[Interaction of the outer membrane pore-forming protein of Yersinia pseudotuberculosis with lipid A and its synthetic analogs]. / Vzaimodeistvie poroobrazuiushchego belka vneshnei membrany Yersinia pseudotuberculosis s lipidom A i ego sinteticheskimi analogami.

Interaction of the major outer membrane protein form Yersinia pseudotuberculosis with lipid A was investigated by intrinsic fluorescence, CD spectroscopy and CsCl gradient centrifugation methods. The protein was shown to have two independent binding sites with an association constant 6.1 x 10(4) M-1. The interaction depends on both the type of the glycoside bond and hydrophilic--hydrophobic balance of the glycolipid molecule.

[Effect of the method of extracting the pore-forming protein from Yersinia pseudotuberculosis on its macromolecular organization]. / Vliianie sposoba ékstrktsii poroobrazuiushchego belka iz Yersinia pseudotuberculosis na ego makromolekuliarnuiu organizatsiiu.

By means of physico-chemical methods, lipid bilayer reconstitution and immunoenzyme assay, macromolecular organization of porin oligomers from Yersinia pseudotuberculosis, isolated by two extraction methods, was studied. Use of SDS and high temperature in the course of the extraction led to a partial denaturation of porin trimers at the level of the tertiary structure, these conformational changes affecting the porin's pore-forming activity and antigenic structure. At the same time, the partially denatured trimers are as stable under the treatment of urea and guanidine hydrochloride as the native protein.

[Features of a protein component of the endotoxin from Yersinia pseudotuberculosis]. / Kharakteristika belkovogo komponenta éndotoksina iz Yersinia pseudotuberculosis.

The protein moiety of endotoxin from Yersinia pseudotuberculosis was found to consist of two polypeptides with apparent molecular masses 40 and 14.5 kDa (4:1 w/w). The major protein (40 kDa) was isolated from the endotoxin pretreated with sodium deoxy cholate by gel chromatography on the Sephadex G-200 column. Comparative study of this protein and oligomeric form of porin from the outer membrane of Y. pseudotuberculosis using SDS--PAGE, velocity sedimentation, lipid bilayer experiments, chemical and serological analyses revealed their identity. The deoxycholate treatment of the endotoxin does not affect complexes of the major protein and LPS.

[Isolation and physico-chemical properties of a protein, included in an endotoxin from Yersinia pseudotuberculosis]. / Vydelenie i fiziko-khimicheskaia kharakteristika belka, vkhodiashchego v sostav éndotaksina iz Yersinia pseudotuberculosis.

A major protein of the endotoxin from Yersinia pseudotuberculosis was isolated from the complex lipid A--protein by treatment with SDS and triton X-100 followed by gel-chromatography on Sephacryl S-300. Protein has apparent molecular mass 40 kDa and alanine as N-terminal amino acid residue. CD and IR spectroscopy conformational changes of the protein molecule in the process of its isolation. The thermal and pH stabilities of the protein were investigated by the methods of intrinsic fluorescence and differential scanning microcalorimetry. The isolated protein revealed two thermal transitions (at 30-35 and 50-55 degrees C), which depend on Ca2+ concentration.

[The use of 13C-NMR spectra of lipopolysaccharide-protein complexes to determine the structure of O-specific polysaccharides]. / Ispol'zovanie spektrov 13C-IaMR lipopolisakharidov-belkovykh kompleksov dlia ustanovleniia stroeniia O-spetsificheskikh polisakharidov.

Lipopolysaccharide-protein complexes are shown to be useful for elucidation of O-specific polysaccharide structures. This approach may be especially useful in studying polysaccharides with labile linkages in the molecule.

[Study of a lipid A-protein complex from Yersinia pseudotuberculosis endotoxin]. / Izuchenie kompleksa lipid A-belok iz éndotoksina Yersinia pseudotuberculosis.

Mild acid hydrolysis of endotoxin of Yersinia pseudotuberculosis afforded a lipid A--protein complex composed of amino acids and all characteristic components of lipid A: glucosamine, dodecanoic, 3-hydroxytetradecanoic acids and phosphorus in a molar ratio of 2 : 1,5 : 2,8 : 1,7, respectively. The protein component of the complex was shown by gel electrophoresis in the presence of sodium dodecylsulphate to consist of two polypeptides with apparent molecular weights of 12000 and 8000. The lipid A--protein complex cross-reacted with antiserum to endotoxin and lipid A antiserum. The components of the complex, namely lipid A and a protein, are associated tightly but noncovalently and can be separated by ultracentrifugation in the sucrose density gradient after treating the complex with sodium dodecylsulphate. The resultant lipid A and the protein manifest a serological activity.