Exploration of the extracellular matrix of the red alga Chondrus crispus reveals unprecedented insights into carrageenan structures.

Carrageenans are major gel forming polysaccharides in the extracellular matrix of the red macroalga Chondrus crispus. These galactans are made of linear chains of repetitive disaccharide motifs based on d-galactose residues alternately linked by β-1,4 and α-1,3 glycosidic bonds. A definite number of disaccharide motifs are known, based on their regular sulfations and the presence of a 3,6-anhydro bridge.

TBL38 atypical homogalacturonan-acetylesterase activity and cell wall microdomain localization in Arabidopsis seed mucilage secretory cells.

Plant cell walls constitute complex polysaccharidic/proteinaceous networks whose biosynthesis and dynamics implicate several cell compartments. The synthesis and remodeling of homogalacturonan pectins involve Golgi-localized methylation/acetylation and subsequent cell wall-localized demethylation/deacetylation. So far, TRICHOME BIREFRINGENCE-LIKE (TBL) family members have been described as Golgi-localized acetyltransferases targeting diverse hemicelluloses or pectins.

Synthesis of galactomannan fragments to help NMR assignment of polysaccharides extracted from lichens.

The synthesis of six model trisaccharides representative of galactomannans produced by lichens was performed through stereoselective glycosylation. These standards include linear and branched galactomannans bearing either galactofuranosyl or galactopyranosyl entities. The complete assignment of H and C signals for both forms of synthetically reduced oligosaccharides was performed.

Ring-Size Memory of Galactose-Containing MS/MS Fragments: Application to the Detection of Galactofuranose in Oligosaccharides and Their Sequencing.

Analysis of glycans remains a difficult task due to their isomeric complexity. Despite recent progress, determining monosaccharide ring size, a type of isomerism, is still challenging due to the high flexibility of the five-membered ring (also called furanose). Galactose is a monosaccharide that can be naturally found in furanose configuration in plant and bacterial polysaccharides.

Fingerprinting of Underivatized Monosaccharide Stereoisomers Using High-Resolution Ion Mobility Spectrometry and Its Implications for Carbohydrate Sequencing.

Although carbohydrates are the most abundant biopolymers on Earth, there is currently no streamlined method to elucidate their complete sequence. Mass spectrometry (MS) alone is blind to many cases of isomerism and thus gives incomplete information for carbohydrates. Notably, the coexistence of numerous stereoisomeric monosaccharide subunits is of special concern.