Trichoderma reesei cellobiohydrolase I with an endoglucanase cellulose-binding domain: action on bacterial microcrystalline cellulose.
Trichoderma reesei cellobiohydrolase I with an endoglucanase cellulose-binding domain: action on bacterial microcrystalline cellulose.
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DOI：
10.1016/s0168-1656(97)00088-6
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发表时间：
1997-09
影响因子：
4.1
通讯作者：
M. Srisodsuk;J. Lehtiö;M. Linder;E. Margolles-clark;T. Reinikainen;T. Teeri
中科院分区：
文献类型：
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作者：
M. Srisodsuk;J. Lehtiö;M. Linder;E. Margolles-clark;T. Reinikainen;T. Teeri
纤维素水解酶由不同的催化结构域和纤维素结合结构域（CBDs）组成。CBD的存在改善了纤维素酶在不溶性底物上的结合和活性，但对其在可溶性底物上的活性没有影响。从里氏木霉纤维生物水解酶中提取的真菌CBD的结构和生化研究揭示了一个楔形结构，其平坦的纤维素结合表面含有三个必需的酪氨酸残基。楔子的表面在所有真菌CBDs中都是严格保守的，而楔子的另一个表面则存在许多差异。在这里，我们研究了这些差异对T. reesei cbi功能的重要性，通过从内切葡聚糖酶EGI中提取的同源CBD取代其CBD。我们的数据表明，除了杂交酶的亲和力略有提高外，结构域交换对CBHI的功能没有显著影响。
Cellulolytic enzymes consist of distinct catalytic and cellulose-binding domains (CBDs). The presence of a CBD improves the binding and activity of cellulases on insoluble substrates but has no influence on their activities on soluble substrates. Structural and biochemical studies of a fungal CBD from Trichoderma reesei cellobiohydrolase I have revealed a wedge shaped structure with a flat cellulose binding surface containing three essential tyrosine residues. The face of the wedge is strictly conserved in all fungal CBDs while many differences occur on the other face of the wedge. Here we have studied the importance of these differences on the function of the T. reesei CBHI by replacing its CBD by a homologous CBD from the endoglucanase, EGI. Our data shows that, apart from slightly improved affinity of the hybrid enzyme, the domain exchange does not significantly influence the function of CBHI.