Structure of beta-Galactosidase from Thermotoga maritima
Structure of beta-Galactosidase from Thermotoga maritima
复制标题
DOI：
10.2210/pdb6s6z/pdb
复制
发表时间：
2020-01
影响因子：
4
通讯作者：
S. Amil;E. Jiménez-Ortega;M. Ramírez-Escudero;David Talens-Perales;J. Marín-Navarro;J. Polaina;J. Sanz-Aparicio;R. Fernández-Leiro
中科院分区：
文献类型：
--
作者：
S. Amil;E. Jiménez-Ortega;M. Ramírez-Escudero;David Talens-Perales;J. Marín-Navarro;J. Polaina;J. Sanz-Aparicio;R. Fernández-Leiro
乳糖不耐症是一种常见的消化系统疾病，影响大部分成年人。症状的严重程度是高度可变的，这取决于对糖的敏感性和消化量。因此，可用于生产无乳糖牛奶和牛奶衍生物的酶具有独特的生物技术重要性。一种这样的情况是海栖热袍菌β-半乳糖苷酶（TmLac）。在这里，我们报告了TmLac在2.0 A分辨率下的冷冻电镜结构。该蛋白质在其C-末端具有一个新解决的结构域，这是Thermotoga属的特征，它促进了一种奇特的八聚体排列。我们已经评估了这种GH 2酶的混合版本的建设上的四级蛋白质结构施加的限制。已在氨基或羧基末端添加来自CBM 2和CBM 9家族的碳水化合物结合模块（CBM），并分析了此类修饰的结构和功能效应。研究结果为合理设计能有效附着于不同载体的杂合酶提供了依据。
Lactose intolerance is a common digestive disorder that affects a large proportion of the adult human population. The severity of the symptoms is highly variable, depending on the susceptibility to the sugar and the amount digested. For that reason, enzymes that can be used for the production of lactose-free milk and milk derivatives have acquired singular biotechnological importance. One such case is Thermotoga maritima β-galactosidase (TmLac). Here, we report the cryo-EM structure of TmLac at 2.0 A resolution. The protein features a newly solved domain at its C-terminus, characteristic of the genus Thermotoga, which promotes a peculiar octameric arrangement. We have assessed the constraints imposed by the quaternary protein structure on the construction of hybrid versions of this GH2 enzyme. Carbohydrate binding modules (CBM) from the CBM2 and CBM9 families have been added at either the amino or carboxy terminus, and the structural and functional effects of such modifications have been analyzed. The results provide a basis for the rational design of hybrid enzymes that can be efficiently attached to different solid supports.