8-epilegionaminic acid

A fourth sugar was found only in LPS of L. pneumophila.12,40 It was initially identified as the L-glycero-o-talo isomer12 but later revised to the D-glycero-D-talo isomer and named 4-epilegionaminic acid (4).11,40 Two more stereoisomers of the nonulosonic acids were found in several other L. pneumophila isolates40 but their configurations have not yet been determined. 

OPS is the same homopolysaccharide that is 8-O-acetylated to varying degrees (from < 10 to > 90%).40 In OPSs of serogroups 5 and 13, 4-epilegionaminic acid is a minor constituent, whereas the major is an unidentified isomer. OPS of serogroup 7 is composed of yet another isomer, whose configuration also remains to be determined. 

Di-A-acetyl-4-epilegionaminic acid is present in LPS of L. pneumophila serogroup l1112 but the site of attachment of this sugar to LPS has not been determined. 

L-glycero-n-galacto isomer (8-epilegionaminic acid, 8eLeg, 3) ... 

Fig. 8. Structures of OPSs containing 8-epilegionaminic acid and shewanellose.

Solvolysis with the same mixture of OPS of S. putrefaciens A6 (29) followed by mild alkaline treatment of the product (49) and hydrolysis of the resultant disaccharide glycoside (50) with 0.5 M CD3C02D in D20 (100 °C, 6.5 h, with NMR control) released a 2,8-anhydro derivative of 8-epilegionaminic acid with a deuterated methylene group (51), together... 

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