Biochemical and Structural Characterization of a Five-domain GH115 α-Glucuronidase from the Marine Bacterium Saccharophagus degradans 2-40T*
Biochemical and Structural Characterization of a Five-domain GH115 α-Glucuronidase from the Marine Bacterium Saccharophagus degradans 2-40T*
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来自海洋细菌 Saccharophagus degradans 2-40T* 的五结构域 GH115 α-葡萄糖醛酸酶的生化和结构表征
DOI：
10.1074/jbc.m115.702944
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
E. Master
中科院分区：
文献类型：
--
作者：
Weijun Wang;R. Yan;B. Nocek;Thu V. Vuong;Rosa Di Leo;Xiaohui Xu;Hong Cui;P. Gatenholm;G. Toríz;M. Tenkanen;A. Savchenko;E. Master
葡萄糖醛酸 (GlcAp) 和/或甲基葡萄糖醛酸 (MeGlcAp) 修饰硬木和针叶软木以及许多谷物中木聚糖的主要形式。因此，葡萄糖醛酸木聚糖的完全利用或转化为糖前体需要主链木聚糖酶以及释放α-(1→2)-连接的(Me)GlcAp侧基的α-葡萄糖醛酸酶的作用。本文中，来自海洋细菌降解糖菌 2-40T 的 GH115 家族酶 SdeAgu115A，表现出对葡糖醛酸木聚糖及其寡聚物的活性，并且优先对与内部吡喃木糖基残基连接的 MeGlcAp 具有活性。还观察到了 NaCl 活化的独特生化特征。 SdeAgu115A的晶体结构揭示了五域结构，其中附加的插入C+域对SdeAgu115A单体的域排列及其二聚化产生了显着影响。结构域 C+ 参与底物结合得到了在该结构域内引入 W773A、W689A 和 F696A 取代后底物抑制减少的支持。除了 Asp-335 之外，Glu-216 的催化重要性也通过位点特异性诱变揭示。一级序列分析表明，超过一半的 GH115 成员共享 SdeAgu115A 结构，从而定义了 GH115 酶的独特原型。
Glucuronic acid (GlcAp) and/or methylglucuronic acid (MeGlcAp) decorate the major forms of xylan in hardwood and coniferous softwoods as well as many cereal grains. Accordingly, the complete utilization of glucuronoxylans or conversion to sugar precursors requires the action of main chain xylanases as well as α-glucuronidases that release the α- (1→2)-linked (Me)GlcAp side groups. Herein, a family GH115 enzymefrom the marine bacterium Saccharophagus degradans 2-40T, SdeAgu115A, demonstrated activity toward glucuronoxylan and oligomers thereof with preference toward MeGlcAp linked to internal xylopyranosyl residues. Unique biochemical characteristics of NaCl activation were also observed. The crystal structure of SdeAgu115A revealed a five-domain architecture, with an additional insertion C+ domain that had significant impact on the domain arrangement of SdeAgu115A monomer and its dimerization. The participation of domain C+ in substrate binding was supported by reduced substrate inhibition upon introducing W773A, W689A, and F696A substitutions within this domain. In addition to Asp-335, the catalytic essentiality of Glu-216 was revealed by site-specific mutagenesis. A primary sequence analysis suggested that the SdeAgu115A architecture is shared by more than half of GH115 members, thus defining a distinct archetype for GH115 enzymes.
DOI：
10.1107/s0907444906019949
发表时间：
2006-08-01
影响因子：
2.2
作者：
Minor, Wladek;Cymborowski, Marcin;Chruszcz, Maksymilian
通讯作者：
Chruszcz, Maksymilian