Uzcategui E, Ruiz A, Montesino R, Johansson G, Pettersson G
Department of Biochemistry, University of Uppsala, Sweden.
J Biotechnol. 1991 Jul;19(2-3):271-85. doi: 10.1016/0168-1656(91)90064-3.
A physico-chemical and structural characterization of three 1,4-beta-D-glucan cellobiohydrolases (EC. 3.2.1.91), isolated from a culture filtrate of the white-rot fungus Phanerochaete chrysosporium, reveals that the cellulolytic enzyme secretion pattern and thus the general degradation strategy for P. chrysosporium is similar to that of Trichoderma reesei. Partial sequence data show that two of the isolated enzymes, i.e., CBHI, pI 3.82 and CBH62, pI 4.85, are homologous with CBHI and EGI from T. reesei; while, the third, i.e., CBH50, pI 4.87, is homologous to T. reesei CBHII. Limited proteolysis with papain cleaved each of the three enzymes into two domains: a core protein which retained full catalytic activity against low molecular weight substrates and a peptide fragment corresponding to the cellulose binding domain, in striking similarity to the structural organization of T. reesei. CBHI and CBH62 have their binding domain located at the C-terminus, whereas in CBH50 it is located at the N-terminus. It is evident that synergistically acting cellobiohydrolases is a general requirement for efficient hydrolysis of crystalline cellulose by cellulolytic fungi.
对从白腐真菌黄孢原毛平革菌培养滤液中分离出的三种1,4-β-D-葡聚糖纤维二糖水解酶（EC. 3.2.1.91）进行的物理化学和结构表征表明，黄孢原毛平革菌的纤维素分解酶分泌模式以及总体降解策略与里氏木霉相似。部分序列数据显示，分离出的两种酶，即pI 3.82的CBHI和pI 4.85的CBH62，与里氏木霉的CBHI和EGI同源；而第三种酶，即pI 4.87的CBH50，与里氏木霉的CBHII同源。用木瓜蛋白酶进行的有限蛋白水解将这三种酶分别切割成两个结构域：一个保留对低分子量底物的全部催化活性的核心蛋白和一个对应于纤维素结合结构域的肽片段，这与里氏木霉的结构组织极为相似。CBHI和CBH62的结合结构域位于C末端，而在CBH50中它位于N末端。显然，协同作用的纤维二糖水解酶是纤维素分解真菌有效水解结晶纤维素的普遍要求。
