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Fig. 2. Structures of the lipid A regions of LPSs used in this study. The structure
of the lipid A region of R. species Sin-1 is not completely
determined but, as that from some other Rhizobiaceae
(Bhat et al., 1994), it is
devoid of phosphate, has 2-aminogluconate in place of glucosamine-1-phosphate,
and contains the very long chain of 27-hydroxyoctacosanoic acid (27-OHC28:0)
that may be ester-linked in the N-acyloxylacyl residue of the distal
glucosamine unit (Basu et al.,
1999). The lipid A regions of the LPSs from three strains of
Legionella pneumophila
(Zähringer et al., 1995;
Kooistra et al., 2002a) are
built upon the same structural model (two residues of 2,3-diaminoglucose
substituted with one very long and five shorter fatty acids), with variations
limited to the length or substituents of the fatty acid chains in positions 2
and 2': R1=H or OH; R2=OH or CH3;
n=18-22 (in strains CS338 and RC1), or n=16-18 (in strain
811).