These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Default biosynthesis pathway for blood group-related glycolipids in human small intestine as defined by structural identification of linear and branched glycosylceramides in a group O Le(a-b-) nonsecretor.
    Author: Angström J, Larsson T, Hansson GC, Karlsson KA, Henry S.
    Journal: Glycobiology; 2004 Jan; 14(1):1-12. PubMed ID: 14514713.
    Abstract:
    Glycoconjugates of the GI tract are important for microbial interactions. The expression of histo-blood group glycosyltransferases governs both the expression of blood group determinants and in part the structure and size of the glycoconjugates. Using neutral glycolipids isolated from the small intestine of a rare blood group O Le(a-b-) ABH secretor-negative (nonsecretor) individual we were able to map the "default" pathway of the individual lacking ABO, Lewis, and secretor glycosyltransferases. Structures were deduced with combined analysis of mass spectrometry (MALDI-TOF and ESI-MS/MS), and 1H NMR (500 and 600 MHz). All structures present at a level >5% were structurally resolved and included two extended structures: Galbeta4(Fucalpha3)GlcNAcbeta3(Galbeta4[Fucalpha3]GlcNAcbeta6)Galbeta4GlcNAcbeta3Galbeta4Glcbeta1Cer and Galbeta3GlcNAcbeta3(Galbeta4[Fucalpha3]GlcNAcbeta6)Galbeta3GlcNAcbeta3Galbeta4Glcbeta1Cer. The first, a novel component, is based on a type 2 chain and bears the Lex glycotopes on both its branches. The second, a major component, is based on a type 1 chain, which bears a 3-linked type 1 precursor (Lec) glycotope and a 6-linked Lex glycotope on its branches. This latter structure is identical to that previously isolated from plasma and characterized by MS and GC-MS but not by NMR. Structural resolution of these structures was supported by reanalysis of the blood group H-active decaosylceramides previously isolated from rat small intestine. Other minor linear monofucosylated penta-, hepta-, and difucosylated octaosylceramides, some bearing blood group determinants, were also identified. The cumulative data were used to define a default biosynthesis pathway where it can be seen that carbohydrate chain extension, in the absence of blood group glycosyltransferases, is controlled and regulated by non-blood group fucosylation and branching with type 2 Galbeta4GlcNAc branches.
    [Abstract] [Full Text] [Related] [New Search]