Synthesis of β‐1,4‐Linked Galactan Side‐Chains of Rhamnogalacturonan I

Abstract

The synthesis of linear‐ and (1→6)‐branched β‐(1→4)‐d‐galactans, side‐chains of the pectic polysaccharide rhamnogalacturonan I is described. The strategy relies on iterative couplings of n‐pentenyl disaccharides followed by a late stage glycosylation of a common hexasaccharide core. Reaction with a covalent linker and immobilization on N‐hydroxysuccinimide (NHS)‐modified glass surfaces allows the generation of carbohydrate microarrays. The glycan arrays enable the study of protein–carbohydrate interactions in a high‐throughput fashion, demonstrated herein with binding studies of mAbs and a CBM.

Branched Pectic Galactan in Phloem-Sieve-Element Cell Walls: Implications for Cell Mechanics

“…Welldefined, single-compound oligosaccharides provide the highest resolution possible when characterizing protein-carbohydrate interactions, provided that the binding interactions are sufficiently strong to be detected. This is especially true when a range of structurally related but distinct glycans are available (for examples, see Clausen et al, 2003;Andersen et al, 2016aAndersen et al, , 2016bSchmidt et al, 2015). In the case of LM26 discussed here, it would have been close to impossible to identify the epitope without access to the appropriate and defined linear and branched galactans.…”

“…To determine the structure recognized by LM26, the antibody was used to probe extensive sets of glycan microarrays with assembled sets of synthetic oligosaccharides relating to those found in plant cell wall glycans (Andersen et al, 2016a). The LM26 MAb was found to bind to three structurally related branched versions of oligo-b-1,4-galactosides.…”

“…3) has been described previously Andersen et al, 2016a). Carbohydrate microarray screening was performed as described previously (Andersen et al, 2016a(Andersen et al, , 2016b.…”

“…3) has been described previously Andersen et al, 2016a). Carbohydrate microarray screening was performed as described previously (Andersen et al, 2016a(Andersen et al, , 2016b. Briefly, deprotected oligosaccharides were functionalized with a heterobifunctional linker 2-(N-methylaminooxy)-1-ethanamine, purified from the excess linker and printed onto NHS-activated Slide-H microarrays from Schott using the ArrayJet Sprint microarray printer.…”

Characterization of the LM5 pectic galactan epitope with synthetic analogues of β-1,4-d-galactotetraose

“…[8] Furthermore, we have previously shown that LM5 does not tolerate β-1,6 branching in order to bind to defined galactans. [12] We were interested in more detailed insight into the binding mode of LM5. From previous work, it was not clear whether the non-reducing end of linear β-1,4-galactans is part of the LM5 epitope.…”