木聚糖酶分子结构与重要酶学性质关系的研究进展

21卷1期2005年1月

生　物　工　程　学　报

Chinese Journal o f Biotechnology V ol.21　N o.1

January 2005

Received :July ,13,2004;Accepted :September ,16,2004.

This w ork was supported by G rant from Chinese National Programs for H igh T echnology Research and Development (863)(N o.2001AA214041).

3C orresponding author.T el :86210268975126;E 2mail :yaobin @.

cn 国家高技术研究与发展计划(863计划)项目资助(N o.2001AA214041)。

木聚糖酶分子结构与重要酶学性质关系的研究进展

R ecent Advances in Structures and R elative E nzyme Pro 2

perties of X ylanase

杨浩萌1

,姚　

斌

13

,范云六

2

Y ANG Hao 2Meng 1,Y AO Bin 13and FAN Y un 2Liu 2

11中国农业科学院饲料研究所,

北京　10008121中国农业科学院生物技术研究所,北京　100081

11F eed Research Institute ,Chinese Academy o f Agricultural Sciences ,Beijing 100081,China 21Biotechnology Research Center ,Chinese Academy o f Agricultural Sciences ,Beijing 100081,China

摘　要　木聚糖是一种多聚五碳糖,是植物细胞中主要的半纤维素成分。木聚糖酶是可将木聚糖降解成低聚木糖和木糖的水解酶,它在饲料、造纸、食品、能源工业和环境科学上有着广阔的应用前景。随着分子生物学、结构生物学的发展及蛋白质工程的应用,对木聚糖酶结构和功能的研究不断深入。这里重点阐述与酶的活性、热稳定性、作用pH 、等电点、底物亲和性及催化效率等重要性质相关的分子结构研究进展,讨论了其进一步的研究发展方向。研究木聚糖酶结构与功能的关系,对进一步加深木聚糖酶作用机制的了解、指导木聚糖酶的分子改良有重要意义。关键词　木聚糖酶,结构与功能,催化残基,热稳定性,pH 性质,底物亲和性中图分类号　Q556 文献标识码　A 文章编号100023061(2005)0120006206

Abstract X ylanase can hydrolyze xylans into xyloolig osaccharides and D 2xylose ,and has great prospect for applications in feed industry ,paper and pulp industry ,food industry and environment science.The study of xylanase had been started in 1960’s.W ith the development and application of the new technologies ,such as m olecular biology ,structural biology and protein engi 2neering ,many progresses have been made in the research of structures and functions of xylanase.This paper reviews the research progress and trend in the structure correlating with the im portant properties of xylanase.Analyses of three 2dimensional structures and properties of mutants have revealed that glutam ine and aspartic acid residues are inv olved in the catalytic mechanism.The therm ostability of xylanase correlated with many factors ,such as disulfide bridges ,salt bridges ,aromatic interactions ,cotent of arginine and proline ,and some multidomain xylanase have therm ostability domains in N or C term inal.But no single mechanism is responsible for the remarkable stability of xylanase.The isoelectic points and reaction pH of xylanase are in fluenced by hydropho 2bicity and content of electric charges.M any researches had dem onstrated that aromatic am ino acid ,histidine ,and tryptophan play an im portant role in im proving enzyme 2substrate affinity.The researches of structures and functions of xylanase are of great signifi 2cance in understanding the catalytic mechanism and directing the im provement of xylanase properties to meet the application requirement.

K ey w ords xylanase ,structure and function ,catalytic residures ,therm ostability ,pH properties ,substrate affinity