X Motifs (x + motif)

Distribution by Scientific Domains

Selected Abstracts

IPSE/alpha-1, a major secretory glycoprotein antigen from schistosome eggs, expresses the Lewis X motif on core-difucosylated N-glycans

FEBS JOURNAL, Issue 10 2006
Manfred Wuhrer
Schistosomes are parasitic flatworms that infect millions of people in (sub)tropical areas around the world. Glycoconjugates of schistosomes play a critical role in the interaction of the different developmental stages of the parasite with the host. In particular, glycosylated components of the eggs produced by the adult worm pairs living in the bloodstream are strongly immunogenic. We have investigated the glycosylation of interleukin-4-inducing factor from schistosome eggs (IPSE/alpha-1), a major secretory egg antigen from Schistosoma mansoni that triggers interleukin-4 production in human basophils, by MS analysis of tryptic glycopeptides. Nanoscale LC-MS(/MS) and MALDI-TOF(/TOF)-MS studies combined with enzymatic degradations showed that monomeric IPSE/alpha-1 contains two N-glycosylation sites, which are each occupied for a large proportion with core-difucosylated diantennary glycans that carry one or more Lewis X motifs. Lewis X has been reported as a major immunogenic glycan element of schistosomes. This is the first report both on the expression of Lewis X on a specific schistosome egg protein and on a protein-specific glycosylation analysis of schistosome eggs. [source]

Hydrolysis of the amyloid ,-peptide (A,) 1,40 between Asp23,Val24 produces non-aggregating fragments.

An electrospray mass spectrometric study
Abstract The aggregation of full-length (residues 1,40) amyloid ,-peptide (A,) and fragments corresponding to residues 1,23 and 24,40 was studied by electrospray mass spectrometry, using gramicidin as a non-aggregating reference. Following a lag period, A,(1,40) at 140 M concentration aggregates with apparent first-order kinetics. Under acidic conditions A,(1,40) undergoes spontaneous cleavage between Asp23,Val24 and to a lesser extent also at two other Asp,X motifs. Incubation in acidic H218O showed incorporation of 18O in fragment A,(1,23), confirming that the Asp23,Val24 peptide bond had been hydrolyzed. Incubation of synthetic A,(1,23) and A,(24,40) peptides with A,(1,40) showed that A,(24,40) remained in solution for several months, that A,(1,23) partly disappeared from solution, whereas A,(1,40) completely disappeared. Further, treatment of sedimentable aggregates formed after co-incubation of the three peptides with hexafluoro-2-propanol or formic acid recovered the intensity of A,(1,40). These data support previous studies showing that the region of A, encompassing residues 16,24 is necessary for aggregation into amyloid fibrils. Copyright 2005 John Wiley & Sons, Ltd. [source]

Production of Lewis x Tetrasaccharides by Metabolically Engineered Escherichia coli

CHEMBIOCHEM, Issue 2 2006
Claire Dumon Dr.
Abstract Two tetrasaccharides carrying the trisaccharidic Lewis x motif on a GlcNAc or a Gal residue were produced on the gram-scale by high-cell-density cultures of metabolically engineered Escherichia coli strains that overexpressed the Helicobacter pylori futA gene for ,-3 fucosyltransferase and the Neisseria meningitidis lgtB gene for ,-4 galactosyltransferase. The first compound Gal,-4(Fuc,-3)GlcNAc,-4GlcNAc was produced by glycosylation of chitinbiose, which was endogenously generated in the bacterial cytoplasm by the successive action of the rhizobial chitin-synthase NodC and the Bacillus circulans chitinase A1, whose genes were additionally expressed in the E. coli strain. The second compound, Gal,-4(Fuc,-3)GlcNAc,-3Gal, was produced from exogenously added Gal by a strain that was deficient in galactokinase activity and overexpressed the additional N. meningitidis lgtA gene for ,-3 N-acetylglucosaminyltransferase. [source]