Multiple isozymes of heparan sulfate/heparin GlcNAc N-deacetylase/GlcN N-sulfotransferase -: Structure and activity of the fourth member, NDST4
Multiple isozymes of heparan sulfate/heparin GlcNAc N-deacetylase/GlcN N-sulfotransferase -: Structure and activity of the fourth member, NDST4
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DOI：
10.1074/jbc.m009606200
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发表时间：
2001-02-23
影响因子：
4.8
通讯作者：
Esko, JD
中科院分区：
文献类型：
--
作者：
Aikawa, J;Grobe, K;Esko, JD
本文报道了脊椎动物硫酸乙酰肝素/肝素家族第四个成员：GlcNAc N-脱乙酰基酶/GlcN N-磺基转移酶的克隆和部分特性，命名为NDST 4。NDST 4推导的氨基酸序列与两个物种的NDST 1、NDST 2和NDST 3具有高度序列同一性。NDST 4定位于人类染色体4 q25 -26，与NDST 3非常接近，位于4 q26 -27。这些观察结果与系统发育数据一起表明，四个NDST从一个共同的祖先基因进化而来，该基因分化为两个亚型，NDST 3/4和NDST 1/2。逆转录-聚合酶链反应分析的各种小鼠组织显示了一个有限的模式NDST 4 mRNA的表达相比，NDST 1和NDST 2，这是丰富和普遍表达。四个小鼠NDST的酶性质的比较显示显着差异的N-脱乙酰化和N-硫酸化活性; NDST 4有弱的脱乙酰酶活性，但高磺基转移酶，而NDST 3具有相反的性质。小鼠和人NDST的磺基转移酶结构域的分子模拟显示在底物结合裂缝内不同的表面电荷分布，表明活性的差异可能反映了对不同底物的偏好。提出了硫酸乙酰肝素生物合成的迭代模型，其中一些NDST同工酶启动链的N-脱乙酰基化和N-硫酸化，而其它的结合到先前修饰的片段以填充或延伸修饰残基的部分。
We report the cloning and partial characterization of the fourth member of the vertebrate hepar-an sulfate/ heparin: GlcNAc N-deacetylase/GlcN N-sulfotransferase family, which we designate NDST4, Full-length cDNA clones containing the entire coding region of 872 amino acids were obtained from human and mouse cDNA libraries. The deduced amino acid sequence of NDST4 showed high sequence identity to NDST1, NDST2, and NDST3 in both species. NDST4 maps to human chromosome 4q25-26, Very close to NDST3, located at 4q26-27. These observations, taken together with phylogenetic data, suggest that the four NDSTs evolved from a common ancestral gene, which diverged to give rise to two subtypes, NDST3/4 and NDST1/2. Reverse transcription-polymerase chain reaction analysis of various mouse tissues revealed a restricted pattern of NDST4 mRNA expression when compared with NDST1 and NDST2, which are abundantly and ubiquitously expressed. Comparison of the enzymatic properties of the four murine NDSTs revealed striking differences in N-deacetylation and N-sulfation activities; NDST4 had weak deacetylase activity but high sulfotransferase, whereas NDST3 had the opposite properties. Molecular modeling of the sulfotransferase domains of the murine and human NDSTs showed varying surface charge distributions within the substrate binding cleft, suggesting that the differences in activity may reflect preferences for different substrates, An iterative model of heparan sulfate biosynthesis is suggested in which some NDST isozymes initiate the N-deacetylation and N-sulfation of the chains, whereas others bind to previously modified segments to fill in or extend the section of modified residues.