Found 2 publications. Displayed publications from 1 to 2
Expand all publications       Show all as text (SweetDB notation)
1. (Article ID: 817)
 
Hood DW, Makepeace K, Deadman ME, Rest RF, Thibault P, Martin A, Richards JC, Moxon ER
Sialic acid in the lipopolysaccharide of Haemophilus influenzae: strain distribution, influence on serum resistance and structural characterization
Molecular Microbiology 33(4) (1999) 679-692
 

A survey of Haemophilus influenzae strains indicated that around one-third of capsular strains and over two-thirds of non-typeable strains included sialic acid in their lipopolysaccharides (LPS). Mutation of the CMP-Neu5Ac synthetase gene (siaB) resulted in a sialylation-deЖcient phenotype. Isogenic pairs, wild type and siaB mutant of two non-typeable strains were used to demonstrate that sialic acid influences resistance to the killing effect of normal human serum but has little effect on attachment to, or invasion of, cultured human epithelial cells or neutrophils. We determine for the Жrst time the site of attachment of sialic acid in the LPS of a non-typeable strain and report that a small proportion of glycoforms include two sialic acid residues in a disaccharide unit.

Lipopolysaccharide, Haemophilus, Haemophilus influenzae, strain, structural, characterization, acid, sialic acid, resistance, serum, serum resistance, distribution, influence

The publication contains the following compound(s):
 

Expand this publication
2. (Article ID: 3145)
 
Fox KL, Cox AD, Gilbert M, Wakarchuk WW, Li J, Makepeace K, Richards JC, Moxon ER, Hood DW
Identification of a bifunctional lipopolysaccharide sialyltransferase in Haemophilus influenzae: Incorporation of disialic acid
Journal of Biological Chemistry 281(52) (2006) 40024-40032
 

The lipopolysaccharide (LPS) of non-typeable H. influenzae (NTHi) can be substituted at various positions by N-acetylneuraminic acid (Neu5Ac). LPS sialylation plays an important role in pathogenesis. The only LPS sialyltransferase characterised biochemically to date in H. influenzae is Lic3A, an α-2,3- sialyltransferase responsible for the addition of Neu5Ac to a lactose acceptor (1). Here we describe a second sialyltransferase, Lic3B, which is a close homologue of Lic3A and present in 60% of NTHi isolates tested. A recombinant form of Lic3B was expressed in E. coli and purified by affinity chromatography. We used synthetic fluorescent acceptors with a terminal lactose or sialyllactose to show that Lic3B has both α-2,3- and α-2,8-sialyltransferase activities. Structural analysis of LPS from lic3B mutant strains of NTHi confirmed only monosialylated species were detectable, whereas disialylated species were detected upon inactivation of lic3A. Furthermore, introduction of lic3B into a lic3B-deficient strain background resulted in a significant increase in sialylation in the recipient strain. Mass spectrometric analysis of LPS indicated that glycoforms containing two Neu5Ac residues were evident that were not present in the LPS of the parent strain. These findings characterise the activity of a second sialyltransferase in H. influenzae, responsible for the addition of di-sialic acid to the LPS. Modification of the LPS by di-sialylation conferred increased resistance of the organism to the killing effects of normal human serum, as compared to mono-sialylated or non-sialylated species, indicating that this modification has biological significance.

Lipopolysaccharide, Haemophilus influenzae, sialyltransferase, sialylation

The publication contains the following compound(s):
 

Expand this publication

Resort publications by:

New query Export IDs Home Help

Execution: 1 sec