Open AccessStructural Elucidation of the Biological Repeating Unit of O‐specific Polysaccharide from Citrobacter Serotype O41
Author(s) -
Ravenscroft Neil,
Dabrowski Janusz,
Romanowska Elzbieta
Publication year - 1995
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1995.0299l.x
Subject(s) - heteronuclear molecule , polysaccharide , residue (chemistry) , stereochemistry , chemistry , serotype , carbohydrate conformation , substituent , nuclear magnetic resonance spectroscopy , biochemistry , biology , microbiology and biotechnology
Sugar analysis of the O‐specific polysaccharide produced by Citrobacter serotype O41 revealed the presence of a hexasaccharide repeating unit, which includes the unusual 3‐amino‐ N ‐( d ‐3′hydroxybutyryl)‐3,6‐dideoxy‐ d ‐galactosyl residue (Fuc3NAcyl). The structure of the repeating unit was determined by extensive use of homo‐ and heteronuclear two‐dimensional NMR spectroscopy, including the application of long‐range 1 H‐ 13 C correlation experiments and NOE studies to establish the sequence of sugar units. Identification of the Glcβ1→2Fuc3NAcylβ→6GlcNAcα1→ sequence at the non‐reducing terminus establishes the biological repeating unit of this O‐specific polysaccharide as: →2Glcβ‐2Fuc3NAcyl‐β1→6GlcNAcα1→(Glcα1‐→2)4Galβ1→3GalNAcβ1→. This structure is similar to that found for the O‐specific polysaccharide isolated from Hafnia alvei strain 1211 [Katzenellenbogen, E., Romanowska, E., Dabrowski, U. & Dabrowski, J. (1991) Eur. J. Biochem. 200 , 401–407], which differs in having an acetyl substituent at O4 of the Fuc3NAcyl residue and a branch point of GalNAcα substituted by Glcβ at O3; these differences are responsible for the only weak serological cross‐reactivity of the two strains.