Wang Juan, Liu Xiang, Liang Yu-He, Li Lan-Fen, Su Xiao-Dong
National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, China.
FEBS Lett. 2008 Sep 3;582(20):2973-8. doi: 10.1016/j.febslet.2008.07.040. Epub 2008 Aug 7.
Glucosamine-6-phosphate (GlcN6P) N-acetyltransferase 1 (GNA1) is a key enzyme in the pathway toward biosynthesis of UDP-N-acetylglucosamine, an important donor substrate for N-linked glycosylation. GNA1 catalyzes the formation of N-acetylglucosamine-6-phosphate (GlcNAc6P) from acetyl-CoA (AcCoA) and the acceptor substrate GlcN6P. Here, we report crystal structures of human GNA1, including apo GNA1, the GNA1-GlcN6P complex and an E156A mutant. Our work showed that GlcN6P binds to GNA1 without the help of AcCoA binding. Structural analyses and mutagenesis studies have shed lights on the charge distribution in the GlcN6P binding pocket, and an important role for Glu156 in the substrate binding. Hence, these findings have broadened our knowledge of structural features required for the substrate affinity of GNA1.
6-磷酸葡萄糖胺（GlcN6P）N-乙酰转移酶1（GNA1）是UDP-N-乙酰葡糖胺生物合成途径中的关键酶，UDP-N-乙酰葡糖胺是N-连接糖基化的重要供体底物。GNA1催化由乙酰辅酶A（AcCoA）和受体底物GlcN6P形成N-乙酰葡糖胺-6-磷酸（GlcNAc6P）。在此，我们报告了人GNA1的晶体结构，包括无配体的GNA1、GNA1-GlcN6P复合物和E156A突变体。我们的研究表明，GlcN6P在没有AcCoA结合的帮助下与GNA1结合。结构分析和诱变研究揭示了GlcN6P结合口袋中的电荷分布，以及Glu156在底物结合中的重要作用。因此，这些发现拓宽了我们对GNA1底物亲和力所需结构特征的认识。
