Lex2B, a phase-variable glycosyltransferase, adds either a glucose or a galactose to Haemophilus influenzae lipopolysaccharide.

Nontypeable Haemophilus influenzae is a commensal that frequently causes otitis media and respiratory tract infections. The lex2 locus encodes a glycosyltransferase that is phase variably expressed and contributes to the significant intrastrain heterogeneity of lipopolysaccharide (LPS) composition i...

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Main Authors: Deadman, M, Hermant, P, Engskog, M, Makepeace, K, Moxon, E, Schweda, E, Hood, D
Format: Journal article
Language:English
Published: 2009
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author Deadman, M
Hermant, P
Engskog, M
Makepeace, K
Moxon, E
Schweda, E
Hood, D
author_facet Deadman, M
Hermant, P
Engskog, M
Makepeace, K
Moxon, E
Schweda, E
Hood, D
author_sort Deadman, M
collection OXFORD
description Nontypeable Haemophilus influenzae is a commensal that frequently causes otitis media and respiratory tract infections. The lex2 locus encodes a glycosyltransferase that is phase variably expressed and contributes to the significant intrastrain heterogeneity of lipopolysaccharide (LPS) composition in H. influenzae. In serotype b strains, Lex2B adds the second beta-glucose in the oligosaccharide extension from the proximal heptose of the triheptose inner core backbone; this extension includes a digalactoside that plays a role in resistance of the bacteria to the killing effect of serum. As part of our studies of the structure and genetics of LPS in nontypeable H. influenzae, we show here that there are allelic polymorphisms in the lex2B sequence that correlate with addition of either a glucose or a galactose to the same position in the LPS molecule across strains. Through exchange of lex2 alleles between strains we show that alteration of a single amino acid at position 157 in Lex2B appears to be sufficient to direct the alternative glucosyl- or galactosyltransferase activities. Allelic exchange strains express LPS with altered structure and biological properties compared to the wild-type LPS. Thus, Lex2B contributes to both inter- and intrastrain LPS heterogeneity through its polymorphic sequences and phase-variable expression.
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spelling oxford-uuid:778b9e63-13fa-4759-a23e-a06fea2814ad2022-03-26T20:24:49ZLex2B, a phase-variable glycosyltransferase, adds either a glucose or a galactose to Haemophilus influenzae lipopolysaccharide.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:778b9e63-13fa-4759-a23e-a06fea2814adEnglishSymplectic Elements at Oxford2009Deadman, MHermant, PEngskog, MMakepeace, KMoxon, ESchweda, EHood, DNontypeable Haemophilus influenzae is a commensal that frequently causes otitis media and respiratory tract infections. The lex2 locus encodes a glycosyltransferase that is phase variably expressed and contributes to the significant intrastrain heterogeneity of lipopolysaccharide (LPS) composition in H. influenzae. In serotype b strains, Lex2B adds the second beta-glucose in the oligosaccharide extension from the proximal heptose of the triheptose inner core backbone; this extension includes a digalactoside that plays a role in resistance of the bacteria to the killing effect of serum. As part of our studies of the structure and genetics of LPS in nontypeable H. influenzae, we show here that there are allelic polymorphisms in the lex2B sequence that correlate with addition of either a glucose or a galactose to the same position in the LPS molecule across strains. Through exchange of lex2 alleles between strains we show that alteration of a single amino acid at position 157 in Lex2B appears to be sufficient to direct the alternative glucosyl- or galactosyltransferase activities. Allelic exchange strains express LPS with altered structure and biological properties compared to the wild-type LPS. Thus, Lex2B contributes to both inter- and intrastrain LPS heterogeneity through its polymorphic sequences and phase-variable expression.
spellingShingle Deadman, M
Hermant, P
Engskog, M
Makepeace, K
Moxon, E
Schweda, E
Hood, D
Lex2B, a phase-variable glycosyltransferase, adds either a glucose or a galactose to Haemophilus influenzae lipopolysaccharide.
title Lex2B, a phase-variable glycosyltransferase, adds either a glucose or a galactose to Haemophilus influenzae lipopolysaccharide.
title_full Lex2B, a phase-variable glycosyltransferase, adds either a glucose or a galactose to Haemophilus influenzae lipopolysaccharide.
title_fullStr Lex2B, a phase-variable glycosyltransferase, adds either a glucose or a galactose to Haemophilus influenzae lipopolysaccharide.
title_full_unstemmed Lex2B, a phase-variable glycosyltransferase, adds either a glucose or a galactose to Haemophilus influenzae lipopolysaccharide.
title_short Lex2B, a phase-variable glycosyltransferase, adds either a glucose or a galactose to Haemophilus influenzae lipopolysaccharide.
title_sort lex2b a phase variable glycosyltransferase adds either a glucose or a galactose to haemophilus influenzae lipopolysaccharide
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