The assembly system for the outer core portion of R1- and R4-type lipopolysaccharides of Escherichia coli. The R1 core-specific beta-glucosyltransferase provides a novel attachment site for O-polysaccharides.
J Biol Chem
; 273(45): 29497-505, 1998 Nov 06.
Article
en En
| MEDLINE
| ID: mdl-9792656
The major core oligosaccharide biosynthesis operons from prototype Escherichia coli strains displaying R1 and R4 lipopolysaccharide core types were polymerase chain reaction-amplified and analyzed. Comparison of deduced products of the open reading frames between the two regions indicate that all but two share total similarities of 94% or greater. Core oligosaccharide structures resulting from nonpolar insertion mutations in each gene of the core OS biosynthesis operon in the R1 strain allowed assignment of all of the glycosyltransferase enzymes required for outer core assembly. The difference between the R1 and R4 core oligosaccharides results from the specificity of the WaaV protein (a beta1, 3-glucosyltransferase) in R1 and WaaX (a beta1, 4-galactosyltransferase) in R4. Complementation of the waaV mutant of the R1 prototype strain with the waaX gene of the R4 strain converted the core oligosaccharide from an R1- to an R4-type lipopolysaccharide core molecule. Aside from generating core oligosaccharide specificity, the unique beta-linked glucopyranosyl residue of the R1 core plays a crucial role in organization of the lipopolysaccharide. This residue provides a novel attachment site for lipid A-core-linked polysaccharides and distinguishes the R1-type LPS from existing models for enterobacterial lipopolysaccharides.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Antígenos O
/
Escherichia coli
/
Glucosiltransferasas
Idioma:
En
Revista:
J Biol Chem
Año:
1998
Tipo del documento:
Article
País de afiliación:
Canadá
Pais de publicación:
Estados Unidos