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@ARTICLE{Seydel:390810,
      author       = {Seydel, Ulrich and Koch, Michel H. J. and Brandenburg,
                      Klaus},
      title        = {{S}tructural {P}olymorphisms of {R}ough {M}utant
                      {L}ipopolysaccharides {R}d to {R}a from {S}almonella
                      minnesota},
      journal      = {Journal of structural biology},
      volume       = {110},
      number       = {3},
      issn         = {1047-8477},
      address      = {San Diego, Calif.},
      publisher    = {Elsevier},
      reportid     = {PUBDB-2017-09865},
      pages        = {232 - 243},
      year         = {1993},
      note         = {EMBL},
      abstract     = {The structural polymorphisms of rough mutant
                      lipopolysaccharides (LPS) Rd, Rc, Rb, and Ra from Salmonella
                      minnesota (strains R4, R7, Rz, R5, R345, and R60,
                      respectively) were investigated as a function of
                      temperature, water content, and Mg$^{2+}$ concentration. The
                      gel to liquid crystalline (B↔α) phase transition
                      temperature (Tc) and the state of order within each phase
                      were measured by Fourier transform infrared spectroscopy.
                      The amount of bound water was determined by differential
                      scanning calorimetry and the three-dimensional structures in
                      each phase state were characterized by synchrotron radiation
                      X-ray diffraction. The results indicate an extremely complex
                      dependence of the structural behavior of LPS on ambient
                      conditions. The B↔α acyl chain melting temperatures at
                      high water contents (95-97\%), Tc = 31 to 32°C for LPS Rd,
                      33 to 35°C for LPS Rc to Rb, and 36°C for LPS Ra, increase
                      with decreasing water content and in the presence of
                      Mg$^{2+}$ cations with a concomitant broadening of the
                      transition range. Below 30 to 50\% water content, no
                      distinct phase transitions can be observed. These effects
                      are most pronounced for LPS with the shortest sugar chains.
                      Below 50\% water content, only lamellur structures can be
                      observed in the temperature range 5 to 80°C, independent of
                      the Mg$^{2+}$ concentration. Above 50\% water concentration,
                      for large [LPS]:[Mg$^{2+}$] molar ratios the predominant
                      structure above Tc is nonlamellar; for smaller
                      [LPS]:[Mg$^{2+}$] molar ratios a superposition of lamellar
                      and nonlamellar structures is found. For all LPS Rd to Rb at
                      low Mg$^{2+}$ concentrations, the phase transition is
                      connected with a change in the three-dimensional structure
                      from lamellar or mixed lamellar/nonlamellar to a pure
                      nonlamellar, probably cubic structure. The tendency to form
                      nonlamellar structures decreases with the length of the core
                      oligosaccharide. At an equimolar ratio of [LPS] and
                      [Mg$^{2+}$] a multibilayered organization is observed. Some
                      of the nonlamellar structures are cubic phases with
                      periodicities between 12 and 16 nm. The molecular dimensions
                      of the single endotoxin molecules in the absence and the
                      presence of external water are estimated from the different
                      lamellar periodicities, including those of free lipid A and
                      deep rough mutant LPS Re. These observations are discussed
                      with respect to the biological importance of LPS as a potent
                      inducer of biological effects in mammals.},
      cin          = {DESY(-2012)},
      ddc          = {540},
      cid          = {$I:(DE-H253)DESY_-2012_-20170516$},
      pnm          = {899 - ohne Topic (POF3-899)},
      pid          = {G:(DE-HGF)POF3-899},
      experiment   = {EXP:(DE-MLZ)NOSPEC-20140101},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:A1993LU06900008},
      pubmed       = {pmid:8373704},
      doi          = {10.1006/jsbi.1993.1026},
      url          = {https://bib-pubdb1.desy.de/record/390810},
}