Novel Endotype Xanthanase from Xanthan-Degrading Microbacterium sp. Strain XT11
Novel Endotype Xanthanase from Xanthan-Degrading Microbacterium sp. Strain XT11
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来自黄原胶降解微杆菌属的新型内型黄原胶酶。
DOI：
10.1128/aem.01800-18
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发表时间：
2018-11
影响因子：
4.4
通讯作者：
Li Xianzhen
中科院分区：
文献类型：
--
作者：
Yang Fan;Li He;Sun Jie;Guo Xiaoyu;Zhang Xinyu;Tao Min;Chen Xiaoyi;Li Xianzhen
本工作表征了一种新型的内型黄原胶酶MiXen，并阐明了MiXen的C-末端碳水化合物结合模块可以显著增强该酶对高度有序的黄原胶的水解活性。序列分析和结构分析表明，MiXen的催化结构域和碳水化合物结合模块分别属于GH 9家族和CBM的新分支。这种黄原胶切割剂有助于进一步揭示黄原胶的降解机理，为生产具有新的理化和生理功能的分子改性黄原胶提供了有效的工具。摘要在一般的水溶液条件下，黄原胶呈现出有序的构象，这使得它的主链很大程度上抵抗已知纤维素酶的降解。因此，由于缺乏高效的水解酶，黄原胶的降解机理尚不清楚。在这里，我们报告的催化特性的混合，黄原胶降解酶确定从属微杆菌。MiXen是一种由952个氨基酸组成的蛋白质，是XT 11菌株所特有的。序列和结构特征均表明MiXen属于GH 9家族的一个新的分支，具有多模块结构，其中催化（α/α）6桶侧接N-末端Ig样结构域和C-末端结构域，其在序列数据库中具有非常少的同源物，并作为碳水化合物结合模块（CBM）起作用。基于圆二色性，剪切依赖性粘度，还原糖和凝胶渗透色谱分析，我们证明了重组MiXen有效地和随机切割糖苷键内的高度有序的黄原胶基板。由于对黄原胶的亲和力降低，不含C-末端CBM结构域的MiXen突变体部分丧失了其黄原胶水解能力，表明CBM结构域通过识别和结合底物来辅助MiXen水解高度有序的黄原胶。此外，侧链取代基和末端甘露糖基残基通过形成屏障显著影响MiXen的活性。总之，本研究的结果提供了深入了解一种新的内源型黄原胶酶的水解机制和酶的性质，这将有利于未来的应用。重要性这项工作的特点是一种新的内型黄原胶酶，MiXen，并阐明了C-末端的碳水化合物结合模块的MiXen可以大大提高酶的水解活性对高度有序的黄原胶。序列分析和结构分析表明，MiXen的催化结构域和碳水化合物结合模块分别属于GH 9家族和CBM的新分支。这种黄原胶切割剂有助于进一步揭示黄原胶的降解机理，为生产具有新的理化和生理功能的分子改性黄原胶提供了有效的工具。
This work characterized a novel endotype xanthanase, MiXen, and elucidated that the C-terminal carbohydrate-binding module of MiXen could drastically enhance the hydrolysis activity of the enzyme toward highly ordered xanthan. Both the sequence and structural analysis demonstrated that the catalytic domain and carbohydrate-binding module of MiXen belong to the novel branch of the GH9 family and CBMs, respectively. This xanthan cleaver can help further reveal the enzymolysis mechanism of xanthan and provide an efficient tool for the production of molecular modified xanthan with new physicochemical and physiological functions. ABSTRACT Under general aqueous conditions, xanthan appears in an ordered conformation, which makes its backbone largely resistant to degradation by known cellulases. Therefore, the xanthan degradation mechanism is still unclear because of the lack of an efficient hydrolase. Here, we report the catalytic properties of MiXen, a xanthan-degrading enzyme identified from the genus Microbacterium. MiXen is a 952-amino-acid protein that is unique to strain XT11. Both the sequence and structural features suggested that MiXen belongs to a new branch of the GH9 family and has a multimodular structure in which a catalytic (α/α)6 barrel is flanked by an N-terminal Ig-like domain and by a C-terminal domain that has very few homologues in sequence databases and functions as a carbohydrate-binding module (CBM). Based on circular dichroism, shear-dependent viscosity, and reducing sugar and gel permeation chromatography analysis, we demonstrated that recombinant MiXen efficiently and randomly cleaved glucosidic bonds within the highly ordered xanthan substrate. A MiXen mutant free of the C-terminal CBM domain partially lost its xanthan-hydrolyzing ability because of decreased affinity toward xanthan, indicating the CBM domain assisted MiXen in hydrolyzing highly ordered xanthan via recognizing and binding to the substrate. Furthermore, side chain substituents and the terminal mannosyl residue significantly influenced the activity of MiXen via the formation of barriers to enzymolysis. Overall, the results of this study provide insight into the hydrolysis mechanism and enzymatic properties of a novel endotype xanthanase that will benefit future applications. IMPORTANCE This work characterized a novel endotype xanthanase, MiXen, and elucidated that the C-terminal carbohydrate-binding module of MiXen could drastically enhance the hydrolysis activity of the enzyme toward highly ordered xanthan. Both the sequence and structural analysis demonstrated that the catalytic domain and carbohydrate-binding module of MiXen belong to the novel branch of the GH9 family and CBMs, respectively. This xanthan cleaver can help further reveal the enzymolysis mechanism of xanthan and provide an efficient tool for the production of molecular modified xanthan with new physicochemical and physiological functions.
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DOI：
10.1271/bbb1961.48.2987
发表时间：
1984-12
期刊：
Agricultural and biological chemistry
影响因子：
--
作者：
M. Tako;Sanehisa Nakamura
通讯作者：
M. Tako;Sanehisa Nakamura
DOI：
10.1155/2014/461540
发表时间：
2014-12-08
期刊：
The Scientific World Journal
影响因子：
--
作者：
Nie W;Peng SJ;Xu J;Liu LR;Wang G;Geng JB
通讯作者：
Geng JB
DOI：
10.1016/0141-8130(87)90068-7
发表时间：
1987-10-01
影响因子：
8.2
作者：
CALLET, F;MILAS, M;RINAUDO, M
通讯作者：
RINAUDO, M
影响因子：
64.8
作者：
SLONEKER, JH;ORENTAS, DG
通讯作者：
ORENTAS, DG
具有生产黄原胶低聚糖潜力的黄原胶降解微杆菌属菌株 XT11 的完整基因组序列
影响因子：
4.1
作者：
Yang Fan;Li Lili;Si Yang;Yang Ming;Guo Xiaoyu;Hou Yingmin;Chen Xiaoyi;Li Xianzhen
通讯作者：
Li Xianzhen