为了分析位于CAZy数据库的CBM67家族的真核α-L-鼠李糖苷酶的CBM的功能，利用ExPASy网站和MEGA 6.0软件进行CBM67家族的真核α-L-鼠李糖苷酶的理化性质分析、进化树的构建，发现CBM67家族的真核α-L-鼠李糖苷酶可被分为三大类，且大部分为疏水性蛋白，氨基酸数量范围为239~377个，分子量（Mr）范围为24540.58~40740.16 u，等电点（pI）范围为3.93~8.74，负电荷残基总数范围为20~29个，正电荷残基总数范围6~33个，原子总数范围为3415~5712，亲水性平均系数范围为-0.077~0.377，；通过ClustalX 2.0程序和Espript网站进行序列比对分析确定CBM67家族真核α-L-鼠李糖苷酶CBM所在的氨基酸区域。采用Discovery Studio 2019软件进行同源建模和分子对接，构建出由12个β折叠组成的α-L-鼠李糖苷酶CBM三维结构，与L-鼠李糖进行分子对接的结果表明CBM能够通过与底物产生强的氢键和范德华力来识别底物，促进酶水解反应的发生。这有助于更好的理解CBM识别并结合底物的结构基础与共性规律，从而为提高CBM的结合力提供理论指导。

The analyses of the physicochemical properties and the construction of the phylogenetic tree for the eukaryotic α-L-rhamnosidase CBM were performed using ExPASy website and MEGA 6.0 software, in order to analyze the function of CBM in the CBM67 family of eukaryotic α-L-rhamnosidase located in the CAZy database. It was found that the eukaryotic α-L-rhamnosidase CBM can be divided into three major classes, and most are hydrophobic proteins, with the number of amino acids in the range of 239~377, molecular weight (Mr) in the range of 24540.58~40740.16 u, isoelectric point (pI) in the range of 3.93~8.74, total number of negatively charged residues in the range of 20~29, total number of positively charged residues in the range of 6~33, total number of atoms in the range of 3415~5712, and average hydrophilicity coefficient in the range of -0.077~0.377. The amino acid region of the eukaryotic α-L-rhamnosidase CBM in the CBM67 family was determined by sequence alignment analysis using the ClustalX 2.0 program and the Espript website. Using the Discovery Studio 2019 software for homology modeling and molecular docking, the three-dimensional structure of α-L-rhamnosidase CBM consisting of 12 β-sheets was constructed. The molecular docking with L-rhamnose revealed that CBM could recognize substrates through producing strong hydrogen bonds and van der Waals forces with L-rhamnose, to promote the occurrence of enzymatic hydrolysis. These results will help us understand better the structural basis and common approaches for CBM to recognize and bind to the substrate, thus, provide theoretical guidance for improving the binding of CBM.

国家自然科学基金项目（U1805235）