Assembly of a β-(1 → 3)-glucan laminarihexaose on ionic liquid support

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2017-2018

This review is the tenth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2018. Also included are papers that describe methods appropriate to glycan and glycoprotein analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, new methods, matrices, derivatization, MALDI imaging, fragmentation and the use of arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Most of the applications are presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. The reported work shows increasing use of combined new techniques such as ion mobility and highlights the impact that MALDI imaging is having across a range of diciplines. MALDI is still an ideal technique for carbohydrate analysis and advancements in the technique and the range of applications continue steady progress.

The Road to Structurally Defined β-Glucans

β-glucans are polymers of glucose that have been isolated from a variety of organisms. Isolated β-glucans have been used for medical purposes for centuries; however, efforts to define the biological activities of β-glucans experimentally were initiated in the 1940's. The diversity of structure associated with isolated β-glucans has impeded said investigations, and efforts to leverage the biological activity of β-glucans for clinical applications. In recognition of the need for defined β-glucans that retain the biological activity of isolated β-glucans, considerable investment has been made to facilitate the synthesis of structurally defined β-glucans. Here, we review the different approaches that have been applied to prepare β-glucans. In addition, we summarize the approaches that have been utilized to conjugate β-glucans to proteins.

Convergent Synthesis of Branched β-Glucan Tridecasaccharides Ready for Conjugation

Structurally defined and pure oligosaccharides corresponding to β-glucans have attracted great attention because of their potential properties as immunostimulating agents and as antigens of vaccine candidates. We herein describe a convergent synthesis of ready-to-conjugate tridecasaccharides composed of a β-1,3-glucan nonasaccharide backbone and a β-1,6-glucan tetrasaccharide branch. The assembly was achieved by employing trichloroacetimidate glycosylations and features the gram-scale preparation of the nonasaccharide backbone and installation of the tetrasaccharide branch involving orthoester rearrangement to the glycoside.