Division of Medicinal Chemistry and Natural Products, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
J Biol Chem. 2011 Jun 3;286(22):19768-76. doi: 10.1074/jbc.M111.224311. Epub 2011 Mar 28.
Heparan sulfate (HS) is a highly sulfated polysaccharide participated in essential physiological functions from regulating cell growth to blood coagulation. HS contains sulfated domains known as N-S domains and low sulfate domains known as N-Ac domains. The distribution of the domain structures is likely governed by the action of glucosaminyl N-deacetylase/N-sulfotransferase (NDST). Here, we sought to determine the substrate specificity of NDST using model substrates and recombinant NDST protein. We discovered that NDST-1 carries out the modification in a highly ordered fashion. The enzyme sulfates the substrate from the nonreducing end toward the reducing end consecutively, leading to the product with a cluster of N-sulfo glucosamine residues. Furthermore, a preexisting N-sulfo glucosamine residue prevents the action of NDST-1 at the residues immediately located at the nonreducing end, allowing the formation of an N-Ac domain. Our results provide the long sought evidence for understanding the formation of sulfated versus nonsulfated domains in the HS isolated from cells and tissues. The study demonstrates the regulating role of NDST-1 in mapping the sulfation patterns of HS.
硫酸乙酰肝素（HS）是一种高度硫酸化的多糖，参与了从调节细胞生长到血液凝固等重要的生理功能。HS 含有已知的硫酸化结构域，称为 N-S 结构域和低硫酸化结构域，称为 N-Ac 结构域。结构域分布的可能性受葡萄糖胺 N-去乙酰基/N-磺基转移酶（NDST）的作用控制。在这里，我们使用模型底物和重组 NDST 蛋白来确定 NDST 的底物特异性。我们发现 NDST-1 以高度有序的方式进行修饰。该酶从非还原端向还原端连续地对底物进行硫酸化，导致产物具有簇状 N-磺基葡萄糖胺残基。此外，预先存在的 N-磺基葡萄糖胺残基阻止 NDST-1 在非还原端紧邻的残基处的作用，从而形成 N-Ac 结构域。我们的结果为理解细胞和组织中分离的 HS 中硫酸化与非硫酸化结构域的形成提供了长期以来寻求的证据。该研究表明 NDST-1 在 HS 硫酸化模式的绘制中起调节作用。
