A New Group of Modular Xylanases in Glycoside Hydrolase Family 8 from Marine Bacteria
A New Group of Modular Xylanases in Glycoside Hydrolase Family 8 from Marine Bacteria
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来自海洋细菌的糖苷水解酶家族 8 中的一组新的模块化木聚糖酶
DOI：
10.1128/aem.01785-18
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发表时间：
2018-09
影响因子：
4.4
通讯作者：
Li Ping-Yi
中科院分区：
文献类型：
--
作者：
Chen Xiu-Lan;Zhao Fang;Yue Yong-Sheng;Zhang Xi-Ying;Zhang Yu-Zhong;Li Ping-Yi
木聚糖酶在天然木聚糖降解中起着至关重要的作用，并已广泛应用于食品加工、动物饲料和硫酸盐纸浆生物漂白等行业。已经发现一些海洋细菌分泌木聚糖酶。海洋细菌木聚糖酶的研究对于阐明海洋中木聚糖的降解机理和开发具有工业应用价值的新型酶具有重要意义。与G.以mesophila XynB为代表，揭示了一组新的海洋细菌GH 8木聚糖酶，它们具有独特的结构域结构，并含有一个新的碳水化合物结合模块。本研究为海洋木聚糖酶的研究提供了新的认识。木聚糖酶在陆地和海洋环境中对木聚糖的降解起着至关重要的作用。来自海洋细菌Glaciecola mesophila KMM 241的内切木聚糖酶XynB是包含具有木聚糖结合能力的长N-末端结构域（NTD）（E44至T562）和糖苷水解酶家族8（GH 8）的催化结构域（CD）（T563至E912）的模块化酶。在这项研究中，长NTD被证实包含三个不同的功能区，即NTD 1（E44至D136），NTD 2（Y137至A193）和NTD 3（L194至T562）。NTD 1主要由8条β链组成，是一种新型的碳水化合物结合模块（CBM），具有木聚糖结合能力，但与已知的CBM没有序列相似性。NTD 2主要形成两个α-螺旋，包含催化结构域的（α/α）6桶的α-螺旋之一，因此对于XynB的活性是必需的，尽管它在序列上远离催化结构域。NTD 3，旁边的催化结构域的序列，被证明是有助于保持XynB的热稳定性。因此，XynB代表了一种具有新结构域结构的木聚糖酶。另外还有四个预测的糖苷水解酶序列与XynB具有相同的结构域结构和较高的序列同一性（≥80%），它们都来自海洋细菌。系统发育分析表明，XynB和这些同源物在GH 8中形成一个新的组，代表一类新的海洋细菌木聚糖酶。这些结果为木聚糖酶，特别是海洋木聚糖酶的研究提供了新的思路。木聚糖酶在天然木聚糖降解中起着至关重要的作用，并已广泛应用于食品加工、动物饲料和硫酸盐纸浆生物漂白等行业。已经发现一些海洋细菌分泌木聚糖酶。海洋细菌木聚糖酶的研究对于阐明海洋中木聚糖的降解机理和开发具有工业应用价值的新型酶具有重要意义。与G.以mesophila XynB为代表，揭示了一组新的海洋细菌GH 8木聚糖酶，它们具有独特的结构域结构，并含有一个新的碳水化合物结合模块。本研究为海洋木聚糖酶的研究提供了新的认识。
Xylanases play a crucial role in natural xylan degradation and have been extensively used in industries such as food processing, animal feed, and kraft pulp biobleaching. Some marine bacteria have been found to secrete xylanases. Characterization of novel xylanases from marine bacteria has significance for both the clarification of xylan degradation mechanisms in the sea and the development of new enzymes for industrial application. With G. mesophila XynB as a representative, this study reveals a new group of the GH8 xylanases from marine bacteria, which have a distinct domain architecture and contain a novel carbohydrate-binding module. Thus, this study offers new knowledge on marine xylanases. ABSTRACT Xylanases play a crucial role in the degradation of xylan in both terrestrial and marine environments. The endoxylanase XynB from the marine bacterium Glaciecola mesophila KMM 241 is a modular enzyme comprising a long N-terminal domain (NTD) (E44 to T562) with xylan-binding ability and a catalytic domain (CD) (T563 to E912) of glycoside hydrolase family 8 (GH8). In this study, the long NTD is confirmed to contain three different functional regions, which are NTD1 (E44 to D136), NTD2 (Y137 to A193), and NTD3 (L194 to T562). NTD1, mainly composed of eight β-strands, functions as a new type of carbohydrate-binding module (CBM), which has xylan-binding ability but no sequence similarity to any known CBM. NTD2, mainly forming two α-helices, contains one of the α-helices of the catalytic domain's (α/α)6 barrel and therefore is essential for the activity of XynB, although it is far away from the catalytic domain in sequence. NTD3, next to the catalytic domain in sequence, is shown to be helpful in maintaining the thermostability of XynB. Thus, XynB represents a kind of xylanase with a new domain architecture. There are four other predicted glycoside hydrolase sequences with the same domain architecture and high sequence identity (≥80%) with XynB, all of which are from marine bacteria. Phylogenetic analysis shows that XynB and these homologs form a new group in GH8, representing a new class of marine bacterial xylanases. Our results shed light on xylanases, especially marine xylanases. IMPORTANCE Xylanases play a crucial role in natural xylan degradation and have been extensively used in industries such as food processing, animal feed, and kraft pulp biobleaching. Some marine bacteria have been found to secrete xylanases. Characterization of novel xylanases from marine bacteria has significance for both the clarification of xylan degradation mechanisms in the sea and the development of new enzymes for industrial application. With G. mesophila XynB as a representative, this study reveals a new group of the GH8 xylanases from marine bacteria, which have a distinct domain architecture and contain a novel carbohydrate-binding module. Thus, this study offers new knowledge on marine xylanases.
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影响因子：
3.1
作者：
A. G. Viana;M. Noseda;A. Gonçalves;M. Duarte;N. Yokoya;M. Matulewicz;A. Cerezo
通讯作者：
A. G. Viana;M. Noseda;A. Gonçalves;M. Duarte;N. Yokoya;M. Matulewicz;A. Cerezo
影响因子：
4.4
作者：
M. Sakka;Yurika Higashi;Tetsuya Kimura;K. Ratanakhanokchai;K. Sakka
通讯作者：
M. Sakka;Yurika Higashi;Tetsuya Kimura;K. Ratanakhanokchai;K. Sakka
影响因子：
4.8
作者：
Fushinobu, S;Hidaka, M;Kitaoka, M
通讯作者：
Kitaoka, M
影响因子：
5.4
作者：
Hoffmam, Zaira B.;Zanphorlin, Leticia M.;Ruller, Roberto
通讯作者：
Ruller, Roberto
DOI：
10.1533/9780857098689.1.23
发表时间：
2013
期刊：
--
影响因子：
--
作者：
A. Usov;N. Zelinsky
通讯作者：
A. Usov;N. Zelinsky