29847-23-2Relevant articles and documents
A (13)C-N.M.R. INVESTIGATION OF GLYCOSYL AZIDES AND OTHER AZIDO SUGARS: STEREOCHEMICAL INFLUENCES ON THE ONE-BOND (13)C-(1)H COUPLING CONSTANTS
Szilagyi, Laszlo,Gyoergydeak, Zoltan
, p. 21 - 42 (1985)
Unambigous (13)C assignments have been obtained, using 2D-n.m.r. techniques, for several glycosyl azides, 6-deoxyglucosyl azides, 2-acylamino-2-deoxyglycosyl azide, and some 2- and 3-azido monosaccharide derivatives.For non-anomeric C-H-bonds the 1JC,Heq. values are 4-9 Hz larger than the 1JC,Hαx. values.A substituent (hydroxyl, acetoxyl, alkoxyl, azido, etc.) in 1,3-diaxial relationship with Hax. significantly increases the value of 1JC,Hαx..Bond-angle distortions in the fused-ring bicyclic systems of some isopropylidene derivatives result in 1JC,Hαx. values being larger than 1JC,Heq. values.Electronic and stericeffects of substituents at non-anomeric carbons may alter the 1JC,H values for anomeric carbons to such an extent that they may no longer be useful for diagnosing anomeric configuration.Bond-angle deformations also influence the (13)C chemical shift differences in α- and β-anomers at C-5 and, to a lesser extent, at C-3.
Radical-Mediated Acyl Thiol-Ene Reaction for Rapid Synthesis of Biomolecular Thioester Derivatives
Lynch, Dylan M.,McLean, Joshua T.,McSweeney, Lauren,Milbeo, Pierre,Scanlan, Eoin M.
supporting information, p. 4148 - 4160 (2021/08/24)
The thiol-ene ‘click’ reaction has emerged as a versatile process for carbon–sulfur bond formation with widespread applications in chemical biology, medicinal chemistry and materials science. Thioesters are key intermediates in a wide range of synthetic and biological processes and efficient methods for their synthesis are of considerable interest. Herein, we report the first examples of acyl-thiol-ene (ATE) for the synthesis of biomolecular thioesters, including peptide, lipid and carbohydrate derivatives. A key finding is the profound effect of the amino acid side chain on the outcome of the ATE reaction. Furthermore, radical generated thioesters underwent efficient S-to-N acyl transfer and desulfurisation to furnish ‘sulfur-free’ ligation products in an overall amidation process with diverse applications for chemical ligation and bioconjugation.
Rapid glycoconjugation with glycosyl amines
Baudendistel, Oliver R.,Rapp, Mareike A.,Steiner, Ulrich E.,Wittmann, Valentin
, p. 14901 - 14906 (2021/12/02)
Conjugation of unprotected carbohydrates to surfaces or probes by chemoselective ligation reactions is indispensable for the elucidation of their numerous biological functions. In particular, the reaction with oxyamines leading to the formation of carbohydrate oximes which are in equilibrium with cyclic N-glycosides (oxyamine ligation) has an enormous impact in the field. Although highly chemoselective, the reaction is rather slow. Here, we report that the oxyamine ligation is significantly accelerated without the need for a catalyst when starting with glycosyl amines. Reaction rates are increased up to 500-fold compared to the reaction of the reducing carbohydrate. For comparison, aniline-catalyzed oxyamine ligation is only increased 3.8-fold under the same conditions. Glycosyl amines from mono- and oligosaccharides are easily accessible from reducing carbohydrates via the corresponding azides by using Shoda's reagent (2-chloro-1,3-dimethylimidazolinium chloride, DMC) and subsequent reduction. Furthermore, glycosyl amines are readily obtained by enzymatic release from N-glycoproteins making the method suited for glycomic analysis of these glycoconjugates which we demonstrate employing RNase B. Oxyamine ligation of glycosyl amines can be carried out at close to neutral conditions which makes the procedure especially valuable for acid-sensitive oligosaccharides. This journal is
Core fucosylation of maternal milk N-glycan evokes B cell activation by selectively promoting the L-fucose metabolism of gut bifidobacterium spp. and lactobacillus spp
Li, Ming,Bai, Yaqiang,Zhou, Jiaorui,Huang, Wei,Yan, Jingyu,Tao, Jia,Fan, Qingjie,Liu, Yang,Mei, Di,Yan, Qiulong,Yuan, Jieli,Malard, Patrice,Wang, Zhongfu,Gu, Jianguo,Tanigchi, Naoyuki,Li, Wenzhe
, (2019/05/10)
The maternal milk glycobiome is crucial for shaping the gut microbiota of infants. Although high core fucosylation catalyzed by fucosyltransferase 8 (Fut8) is a general feature of human milk glycoproteins, its role in the formation of a healthy microbiota has not been evaluated. In this study, we found that the core-fucosylated N-glycans in milk of Chinese mothers selectively promoted the colonization of specific gut microbial groups, such as Bifidobacterium spp. and Lactobacillus spp. in their breast-fed infants during lactation. Compared with Fut8+/+ (WT) mouse-fed neonates, the offspring fed by Fut8+/-maternal mice had a distinct gut microbial profile, which was featured by a significant reduction of Lactobacillus spp., Bacteroides spp., and Bifidobacterium spp. and increased abundance of members of the Lachnospiraceae NK4A136 group and Akkermansia spp. Moreover, these offspring mice showed a lower proportion of splenic CD19+ CD69+ B lymphocytes and attenuated humoral immune responses upon ovalbumin (OVA) immunization. In vitro studies demonstrated that the chemically synthesized core-fucosylated oligosaccharides possessed the ability to promote the growth of tested Bifidobacterium and Lactobacillus strains in minimal medium. The resulting L-fucose metabolites, lactate and 1,2-propanediol, could promote the activation of B cells via the B cell receptor (BCR)-mediated signaling pathway. IMPORTANCE This study provides novel evidence for the critical role of maternal milk protein glycosylation in shaping early-life gut microbiota and promoting B cell activation of neonates. The special core-fucosylated oligosaccharides might be promising prebiotics for the personalized nutrition of infants.
