Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602.
Department of Chemistry, University of Georgia, Athens, GA 30602.
Proc Natl Acad Sci U S A. 2017 Jul 3;114(27):6954-6959. doi: 10.1073/pnas.1701785114. Epub 2017 Jun 19.
Despite mammalian glycans typically having highly complex asymmetrical multiantennary architectures, chemical and chemoenzymatic synthesis has almost exclusively focused on the preparation of simpler symmetrical structures. This deficiency hampers investigations into the biology of glycan-binding proteins, which in turn complicates the biomedical use of this class of biomolecules. Herein, we describe an enzymatic strategy, using a limited number of human glycosyltransferases, to access a collection of 60 asymmetric, multiantennary human milk oligosaccharides (HMOs), which were used to develop a glycan microarray. Probing the array with several glycan-binding proteins uncovered that not only terminal glycoepitopes but also complex architectures of glycans can influence binding selectivity in unanticipated manners. N- and O-linked glycans express structural elements of HMOs, and thus, the reported synthetic principles will find broad applicability.
尽管哺乳动物糖通常具有高度复杂的不对称多臂结构，但化学和化学酶合成几乎完全专注于制备更简单的对称结构。这种缺陷阻碍了对糖结合蛋白生物学的研究，这反过来又使这类生物分子的生物医学用途复杂化。在此，我们描述了一种使用少量人类糖基转移酶的酶促策略，用于获得 60 种不对称的、多臂的人乳寡糖（HMO）的集合，这些寡糖被用于开发糖基微阵列。用几种糖结合蛋白探测该阵列表明，不仅末端糖基表位，而且聚糖的复杂结构也可以以出人意料的方式影响结合选择性。N-和 O-连接的糖表达 HMO 的结构元件，因此，所报道的合成原理将具有广泛的适用性。
