Computational studies on glycosaminoglycan recognition of sialyl transferases.
Computational studies on glycosaminoglycan recognition of sialyl transferases.
复制标题
唾液酸转移酶糖胺聚糖识别的计算研究。
DOI：
10.1093/glycob/cwad040
复制
发表时间：
2023
期刊：
影响因子：
4.3
通讯作者：
Desai,UmeshR
中科院分区：
文献类型：
--
作者：
Sankaranarayanan,NehruViji;Sistla,Srinivas;Nagarajan,Balaji;Chittum,JohnE;Lau,JosephTY;Desai,UmeshR
尽管进行了几十年的研究，但糖胺多聚糖(GAG)与唾液酸基转移酶(STS)的相互作用尚不清楚。利用我们的内部组合虚拟文库筛选(CVLS)技术，我们研究了7种人类亚型，包括ST6GAL1、ST6GAL2、ST3GAL1、ST3GAL3、ST3GAL4、ST3GAL5和ST3GAL6，并预测GAG，特别是硫酸乙酰肝素(HS)，可能与STS有差异结合。详尽的CVLS和分子动力学研究表明，HS的共同六糖序列优先识别ST6GAL1，该序列与供体底物CMP-SIA的结合部位重叠。有趣的是，CVLS没有将HS罕见的3-O-硫酸盐修饰在ST6GAL1识别中归因于任何特殊的作用。计算预测用荧光光谱研究进行了检验，证实了HS比其他GAG更能被识别。观察到GAG与ST6GAL1的结合是典型的链长依赖性结合，与聚合物HS的亲和力为~65nM。生物物理研究也证实了CMP-SIA与HS寡糖和CS多糖直接竞争结合ST6GAL1。总体而言，我们新的观察到的GAG与ST6GAL1高亲和力结合并与供体底物竞争可能是重要的，因为调节细胞上的糖链底物的唾液酸化具有相当大的生理/病理后果。我们的工作也为开发基于GAG的ST6GAL1化学探针提供了可能性。
Despite decades of research, glycosaminoglycans (GAGs) have not been known to interact with sialyl transferases (STs). Using our in-house combinatorial virtual library screening (CVLS) technology, we studied seven human isoforms, including ST6GAL1, ST6GAL2, ST3GAL1, ST3GAL3, ST3GAL4, ST3GAL5, and ST3GAL6, and predicted that GAGs, especially heparan sulfate (HS), are likely to differentially bind to STs. Exhaustive CVLS and molecular dynamics studies suggested that the common hexasaccharide sequence of HS preferentially recognized ST6GAL1 in a site overlapping the binding site of the donor substrate CMP-Sia. Interestingly, CVLS did not ascribe any special role for the rare 3-O-sulfate modification of HS in ST6GAL1 recognition. The computational predictions were tested using spectrofluorimetric studies, which confirmed preferential recognition of HS over other GAGs. A classic chain length-dependent binding of GAGs to ST6GAL1 was observed with polymeric HS displaying a tight affinity of ~65 nM. Biophysical studies also confirmed a direct competition between CMP-Sia and an HS oligosaccharide and CS polysaccharide for binding to ST6GAL1. Overall, our novel observation that GAGs bind to ST6GAL1 with high affinity and compete with the donor substrate is likely to be important because modulation of sialylation of glycan substrates on cells has considerable physiological/pathological consequences. Our work also brings forth the possibility of developing GAG-based chemical probes of ST6GAL1.