Topological and enzymatic analysis of human Alg2 mannosyltransferase reveals its role in lipid-linked oligosaccharide biosynthetic pathway.
Topological and enzymatic analysis of human Alg2 mannosyltransferase reveals its role in lipid-linked oligosaccharide biosynthetic pathway.
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人 Alg2 甘露糖基转移酶的拓扑和酶学分析揭示了其在脂质连接寡糖生物合成途径中的作用
DOI：
10.1038/s42003-022-03066-9
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发表时间：
2022-02-08
影响因子：
5.9
通讯作者：
Gao XD
中科院分区：
文献类型：
--
作者：
Xiang MH;Xu XX;Wang CD;Chen S;Xu S;Xu XY;Dean N;Wang N;Gao XD
N-糖基化始于内质网（ER）上脂联寡糖（LLO）的生物合成。Alg 2甘露糖基转移酶将α 1，3-和α 1，6-甘露糖（Man）以任一顺序添加到ManGlcNAc 2-焦磷酸-多萜醇（M1 Gn 2-PDol）上，以产生支链M3 Gn 2-PDol产物。酵母Alg 2通过4个疏水结构域与内质网膜相互作用。出乎意料的是，我们发现Alg 2结构在酵母和人类之间存在差异。人Alg 2（hAlg 2）通过单个膜结合结构域与ER结合，并且在体外明显更稳定。利用这些特性开发了液相色谱-质谱定量动力学分析研究纯化hAlg 2。在生理条件下，hAlg 2倾向于在加入α 1，6-Man之前将α 1，3-Man转移到M1 Gn 2上。然而，这种偏好会被过量的GDP-Man供体或增加的M1 Gn 2底物水平所改变，这两者都会触发M2 Gn 2（α-1，6）-PDol的产生。这些结果表明Alg 2可能通过控制M2 Gn 2（α-1，6）中间产物的积累来调节LLO生物合成途径。尽管保守的N-糖基化，人类和酵母Alg 2的结构已经分化与不同的ER结合拓扑结构。人酶比酵母直向同源物更稳定，其活性受供体或受体底物浓度的调节。
N-glycosylation starts with the biosynthesis of lipid-linked oligosaccharide (LLO) on the endoplasmic reticulum (ER). Alg2 mannosyltransferase adds both the α1,3- and α1,6-mannose (Man) onto ManGlcNAc2-pyrophosphate-dolichol (M1Gn2-PDol) in either order to generate the branched M3Gn2-PDol product. The well-studied yeast Alg2 interacts with ER membrane through four hydrophobic domains. Unexpectedly, we show that Alg2 structure has diverged between yeast and humans. Human Alg2 (hAlg2) associates with the ER via a single membrane-binding domain and is markedly more stable in vitro. These properties were exploited to develop a liquid chromatography-mass spectrometry quantitative kinetics assay for studying purified hAlg2. Under physiological conditions, hAlg2 prefers to transfer α1,3-Man onto M1Gn2 before adding the α1,6-Man. However, this bias is altered by an excess of GDP-Man donor or an increased level of M1Gn2 substrate, both of which trigger production of the M2Gn2(α-1,6)-PDol. These results suggest that Alg2 may regulate the LLO biosynthetic pathway by controlling accumulation of M2Gn2 (α-1,6) intermediate. Despite the conservation of N-glycosylation, human and yeast Alg2 structures have diverged with distinct ER-binding topologies. The human enzyme is more stable than the yeast orthologue, and its activity is modulated by the concentration of donor or acceptor substrate.
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影响因子：
2.9
作者：
Larkin A;Imperiali B
通讯作者：
Imperiali B
影响因子：
5.6
作者：
Gordon, Roni D.;Sivarajah, Prashanth;Rini, James M.
通讯作者：
Rini, James M.
影响因子：
48
作者：
Lorenz, H;Hailey, DW;Lippincott-Schwartz, J
通讯作者：
Lippincott-Schwartz, J
DOI：
10.1039/p19920002087
发表时间：
1992-08-21
期刊：
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1
影响因子：
--
作者：
FLITSCH, SL;PINCHES, HL;TURNER, NJ
通讯作者：
TURNER, NJ
影响因子：
4.3
作者：
JACKSON, BJ;KUKURUZINSKA, MA;ROBBINS, P
通讯作者：
ROBBINS, P