Identification of the binding roles of terminal and internal glycan epitopes using enzymatically synthesized N-glycans containing tandem epitopes.
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ABSTRACT: Glycans play diverse roles in a wide range of biological processes. Research on glycan-binding events is essential for learning their biological and pathological functions. However, the functions of terminal and internal glycan epitopes exhibited during binding with glycan-binding proteins (GBPs) and/or viruses need to be further identified. Therefore, a focused library of 36 biantennary asparagine (Asn)-linked glycans with some presenting tandem glycan epitopes was synthesized via a combined Core Isolation/Enzymatic Extension (CIEE) and one-pot multienzyme (OPME) synthetic strategy. These N-glycans include those containing a terminal sialyl N-acetyllactosamine (LacNAc), sialyl Lewis x (sLex) and Sia?2-8-Sia?2-3/6-R structures with N-acetylneuraminic acid (Neu5Ac) or N-glycolylneuraminic acid (Neu5Gc) sialic acid form, LacNAc, Lewis x (Lex), ?-Gal, and Gal?1-3-Lex; and tandem epitopes including ?-Gal, Lex, Gal?1-3-Lex, LacNAc, and sialyl LacNAc, presented with an internal sialyl LacNAc or 1-2 repeats of an internal LacNAc or Lex component. They were synthesized in milligram-scale, purified to over 98% purity, and used to prepare a glycan microarray. Binding studies using selected plant lectins, antibodies, and viruses demonstrated, for the first time, that when interpreting the binding between glycans and GBPs/viruses, not only the structure of the terminal glycan epitopes, but also the internal epitopes and/or modifications of terminal epitopes needs to be taken into account.
SUBMITTER: Wu Z
PROVIDER: S-EPMC5951163 | biostudies-literature | 2016 Nov
REPOSITORIES: biostudies-literature
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