Structural Insight into and Mutational Analysis of Family 11 Xylanases: Implications for Mechanisms of Higher pH Catalytic Adaptation.
Structural Insight into and Mutational Analysis of Family 11 Xylanases: Implications for Mechanisms of Higher pH Catalytic Adaptation.
复制标题
11 族木聚糖酶的结构洞察和突变分析：对较高 pH 催化适应机制的影响
DOI：
10.1371/journal.pone.0132834
复制
发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Ma Y
中科院分区：
文献类型：
--
作者：
Bai W;Zhou C;Zhao Y;Wang Q;Ma Y
为了了解家族11木聚糖酶的较高pH催化适应的分子基础，我们比较了碱性、中性和酸性活性木聚糖酶的结构，并分析了来自嗜碱芽孢杆菌SN 5的木聚糖酶Xyn 11 A-LC的突变体。结果表明，碱性活性木聚糖酶相对于非碱性活性对应物具有增加的带电残基含量、增加的带负电残基与带正电残基的比率以及降低的Ser、Thr和Tyr残基含量。在β6和β7链之间，碱性木聚糖酶用α-螺旋取代了非碱性木聚糖酶中的卷曲或转角。与非碱性木聚糖酶相比，碱性活性酶插入了一段富含带电残基的7个氨基酸，这可能有利于木聚糖酶在碱性条件下发挥功能。分子表面的正电荷残基和离子键可能在家族11木聚糖酶的高pH催化适应中起重要作用。通过结构比较、序列比对和突变分析，发现与酸/碱催化剂相邻的6个氨基酸（Glu 16、Trp 18、Asn 44、Leu 46、Arg 48和Ser 187，编号基于Xyn 11 A-LC）负责在较高pH条件下的木聚糖酶功能。我们的研究结果将有助于理解家族11木聚糖酶的高pH催化适应的分子机制和工程木聚糖酶，以适应工业应用。
To understand the molecular basis of higher pH catalytic adaptation of family 11 xylanases, we compared the structures of alkaline, neutral, and acidic active xylanases and analyzed mutants of xylanase Xyn11A-LC from alkalophilic Bacillus sp. SN5. It was revealed that alkaline active xylanases have increased charged residue content, an increased ratio of negatively to positively charged residues, and decreased Ser, Thr, and Tyr residue content relative to non-alkaline active counterparts. Between strands β6 and β7, alkaline xylanases substitute an α-helix for a coil or turn found in their non-alkaline counterparts. Compared with non-alkaline xylanases, alkaline active enzymes have an inserted stretch of seven amino acids rich in charged residues, which may be beneficial for xylanase function in alkaline conditions. Positively charged residues on the molecular surface and ionic bonds may play important roles in higher pH catalytic adaptation of family 11 xylanases. By structure comparison, sequence alignment and mutational analysis, six amino acids (Glu16, Trp18, Asn44, Leu46, Arg48, and Ser187, numbering based on Xyn11A-LC) adjacent to the acid/base catalyst were found to be responsible for xylanase function in higher pH conditions. Our results will contribute to understanding the molecular mechanisms of higher pH catalytic adaptation in family 11 xylanases and engineering xylanases to suit industrial applications.
登录
查看更多内容
影响因子：
2.8
作者：
Bai, Wenqin;Xue, Yanfen;Ma, Yanhe
通讯作者：
Ma, Yanhe
影响因子：
5.8
作者：
Gouet, P;Courcelle, E;Métoz, F
通讯作者：
Métoz, F
影响因子：
2.9
作者：
Joshi, MD;Sidhu, G;McIntosh, LP
通讯作者：
McIntosh, LP
DOI：
10.1046/j.1432-1033.2003.03496.x
发表时间：
2003-04-01
期刊：
EUROPEAN JOURNAL OF BIOCHEMISTRY
影响因子：
--
作者：
Hakulinen, N;Turunen, O;Rouvinen, J
通讯作者：
Rouvinen, J
影响因子：
2.7
作者：
Bai, Wenqin;Zhou, Cheng;Ma, Yanhe
通讯作者：
Ma, Yanhe