Structural basis of substrate recognition and catalysis by fucosyltransferase 8
Structural basis of substrate recognition and catalysis by fucosyltransferase 8
复制标题
DOI：
10.1074/jbc.ra120.013291
复制
发表时间：
2020-05-08
影响因子：
4.8
通讯作者：
Goddard-Borger, Ethan D.
中科院分区：
文献类型：
--
作者：
Jarva, Michael A.;Dramicanin, Marija;Goddard-Borger, Ethan D.
岩藻糖基转移酶8(FUT8)对N-糖链最内侧的GlcNAc进行岩藻糖基化，是复合型和杂合型N-糖链成熟过程中的重要步骤。这一简单的修饰可以极大地影响糖蛋白的活性和半衰期，影响与了解某些癌症的侵袭性、mAb疗法的发展以及先天性糖基化障碍的病因学相关的影响。FUT8的受体底物偏好已经得到了很好的表征，并为理解高尔基体中N-糖链的成熟提供了一个框架；然而，这些底物偏好的结构基础和催化作用的实现机制仍不清楚。在这里，我们描述了小鼠和人FUT8的几种结构，它们处于载脂蛋白状态，并与GDP(模拟供体底物)和糖肽受体底物(1.80？2.50？决议。这些结构提供了与供体底物结合相关的独特构象变化的见解，岩藻糖基转移酶协调GDP的常见策略，定义受体底物偏好的特征，以及酶催化的可能机制。结合分子动力学模拟，结构还揭示了FUT8二聚如何在定义受体底物结合位置方面发挥重要作用。总而言之，这些信息显著地建立在我们对核心岩藻糖化过程的理解上。
Fucosylation of the innermost GlcNAc of N-glycans by fucosyltransferase 8 (FUT8) is an important step in the maturation of complex and hybrid N-glycans. This simple modification can dramatically affect the activities and half-lives of glycoproteins, effects that are relevant to understanding the invasiveness of some cancers, development of mAb therapeutics, and the etiology of a congenital glycosylation disorder. The acceptor substrate preferences of FUT8 are well-characterized and provide a framework for understanding N-glycan maturation in the Golgi; however, the structural basis of these substrate preferences and the mechanism through which catalysis is achieved remain unknown. Here we describe several structures of mouse and human FUT8 in the apo state and in complex with GDP, a mimic of the donor substrate, and with a glycopeptide acceptor substrate at 1.80?2.50 ? resolution. These structures provide insights into a unique conformational change associated with donor substrate binding, common strategies employed by fucosyltransferases to coordinate GDP, features that define acceptor substrate preferences, and a likely mechanism for enzyme catalysis. Together with molecular dynamics simulations, the structures also revealed how FUT8 dimerization plays an important role in defining the acceptor substrate-binding site. Collectively, this information significantly builds on our understanding of the core fucosylation process.