利用透射电子显微镜研究真菌内切-β-1,4-甘露聚糖酶和β-1,4-甘露糖苷酶对甘露聚糖I和II晶体的降解作用。

Degradation of mannan I and II crystals by fungal endo-beta-1,4-mannanases and a beta-1,4-mannosidase studied with transmission electron microscopy.

作者信息

Hägglund P, Sabini E, Boisset C, Wilson K, Chanzy H, Stålbrand H

机构信息

Department of Biochemistry, Center for Chemistry and Chemical Engineering, Lund University, PO Box 124, S-221 00, Lund, Sweden.

出版信息

Biomacromolecules. 2001 Fall;2(3):694-9. doi: 10.1021/bm010006w.

DOI:10.1021/bm010006w

PMID:11710023

Abstract

We have used the endo-beta-1,4-mannanase from Trichoderma reesei (Tr Man5A), the endo-beta-1,4-mannanase from Aspergillus niger (An Man5A) and the exo-beta-1,4-mannosidase from A. niger (An Mnd2A) to follow the enzymatic degradation of mannan I and II crystals. The degradation process was studied by transmission electron microscopy and also followed by analysis of the released soluble reducing sugars. The mannan crystals were degraded by the endo-beta-1,4-mannanases and to a lesser extent by the exo-beta-1,4-mannosidase. The observed hydrolysis pattern on mannan I crystals is fully consistent with the current view of the molecular structure of these crystals. The molecular organization of the mannan chains in mannan II crystals is less clear and the digestion results give some further information about the ultrastructure of mannan II. In addition, insight is provided into the mode of the enzymatic attack on the crystals of mannan I and mannan II.

摘要

我们使用了里氏木霉的内切-β-1,4-甘露聚糖酶（Tr Man5A）、黑曲霉的内切-β-1,4-甘露聚糖酶（An Man5A）以及黑曲霉的外切-β-1,4-甘露糖苷酶（An Mnd2A）来跟踪甘露聚糖I和II晶体的酶促降解过程。通过透射电子显微镜对降解过程进行了研究，并对释放出的可溶性还原糖进行了分析。甘露聚糖晶体被内切-β-1,4-甘露聚糖酶降解，外切-β-1,4-甘露糖苷酶的降解程度较小。在甘露聚糖I晶体上观察到的水解模式与目前对这些晶体分子结构的看法完全一致。甘露聚糖II晶体中甘露聚糖链的分子组织尚不清楚，消化结果为甘露聚糖II的超微结构提供了一些进一步的信息。此外，还深入了解了对甘露聚糖I和甘露聚糖II晶体的酶促攻击模式。