A dual role for the lex2 locus: identification of galactosyltransferase activity in non-typeable Haemophilus influenzae strains 1124 and 2019
2009 (English)In: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 344, no 5, 632-641 p.Article in journal (Refereed) Published
Lipopolysaccharide (LPS) of Haemophilus influenzae comprises a conserved tri-L-glycero-D-manno-heptosyl inner-core moiety (L-alpha-D-Hepp-(1 -> 2)-[PEtn -> 6]-L-alpha-D-Hepp-(1 -> 3)-[beta-D-Glclp-(1 -> 4)]-L-alpha-D-Hepp-(1 -> 5)-alpha-Kdop) to which addition of beta-D-Glcp to O-4 of Glcl in serotype b strains is controlled by the gene lex2B. In non-typeable H. influenzae strains 1124 and 2019, however, a beta-D-Galp is linked to O-4 of Glcl. In order to test the hypothesis that the 1ex2 locus is involved in the expression Of beta-D-Galp-(1 -> 4-beta-D-Glcp-(1 -> - from Hepl, 1ex2B was inactivated in strains 1124 and 2019, and LPS glycoform populations from the resulting mutant strains were investigated. Detailed structural analyses using NMR techniques and electrospray-ionisation mass spectrometry (ESIMS) on O-cleacylated LPS and core oligosaccharide material (OS), as well as ESIMS" on permethylated dephosphorylated OS, indicated both lex2B mutant strains to express only beta-D-Glcp extensions from Hepl. This provides strong evidence that Lex2B functions as a galactosyltransferase adding a beta-D-Galp to O-4 of Glcl in these strains, indicating that allelic polymorphisms in the lex2B sequence direct alternative functions of the gene product.
Place, publisher, year, edition, pages
2009. Vol. 344, no 5, 632-641 p.
Biochemistry and Molecular Biology
IdentifiersURN: urn:nbn:se:sh:diva-13910DOI: 10.1016/j.carres.2009.01.005ISI: 000265321500010PubMedID: 19211098ScopusID: 2-s2.0-62749180259OAI: oai:DiVA.org:sh-13910DiVA: diva2:465010