Synthesis of the beta anomer of the spacer-equipped tetrasaccharide side chain of the major glycoprotein of the Bacillus anthracis exosporium.
The beta glycoside of the tetrasaccharide sequence beta-Ant-(1-->3)-alpha-l-Rhap-(1-->3)-alpha-l-Rhap-(1-->2)-l-Rhap, whose aglycon allows conjugation to proteins, was synthesized for the first time. A stepwise synthetic approach was applied with thioglycosides as glycosyl donors, and the beta anomer of the compound was obtained equipped with a spacer group whose further transformation allows conjugation to suitable carriers. To synthesize the beta-anthrosyl linkage with high stereoselectivity, a linker-equipped rhamnotriose derivative was glycosylated with ethyl 4-azido-3-O-benzyl-2-O-bromoacetyl-4,6-dideoxy-1-thio-beta-d-glucopyranoside. Further functionalization of the tetrasaccharide thus obtained, followed by deprotection, gave the target substance.
Adamo
Roberto
R
NIDDK, LMC, National Institutes of Health, Bethesda, MD 20892-0815, USA.
Saksena
Rina
R
Kovác
Pavol
P
D001408:Bacillus anthracis / Q000378:metabolism*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000096:biosynthesis* / Q000737:chemistry
D008562:Membrane Glycoproteins; D009844:Oligosaccharides