口腔致病菌变形链球菌Smu.776蛋白的制备、结晶及初级晶体学分析(英文)  

Preparation, Crystallization and Preliminary X-ray Crystallographic Analysis of Smu.776 From Caries Pathogen Streptococcus mutans

作　　者：王开拓[1] 李兰芬[1] 张晓嫣[1] 梁宇和[1] 魏世成[2] 苏晓东[1] 

机构地区：[1]蛋白质工程和植物基因工程国家重点实验室北京大学生命科学学院,北京100871 [2]北京大学口腔医学院,北京100081

出　　处：《生物化学与生物物理进展》2007年第2期176-179,共4页Progress In Biochemistry and Biophysics

基　　金：国家自然科学基金重点项目(30530190);北京大学985和211工程项目资助;梁宇和受霍英东教育基金优选资助课题资助(94017)~~

摘　　要：变形链球菌smu.776基因编码一段含有385个氨基酸的蛋白质,其功能可能为依赖于腺苷甲硫氨酸的甲基转移酶.smu.776的DNA片段被克隆到表达载体pET28a后,在大肠杆菌BL21(DE3)菌株中过量表达得到很好的产量.产物Smu.776蛋白通过Ni2+亲和柱和分子筛柱层析两步得到纯化.采用悬滴气象扩散法得到了Smu.776蛋白的晶体.X射线衍射分辨率达到2.0!,晶体属单斜空间群C2,晶格参数为a=168.47",b=50.66#,c=53.96$,β=104.22°.每个最小不对称单元内含有一个蛋白质分子,溶剂含量为51.3%.The gene smu.776 encodes a possible S-adenosylmethionine-dependent methyltransferase of 385 residues in Streptococcus mutans, a primary pathogen for human dental caries. The DNA fragment of smu.776 was cloned into pET28a and expressed in good amount from the E. coil strain BL21 （DE3）. Smu.776 protein was purified to homogeneity in a two-step procedure of Ni^2＋ chelating and size exclusion chromatography. Crystals were obtained by hanging-drop vapor diffusion method and diffracted to 2.0A resolution. The crystal belongs to orthorhombic space group C2 with cell dimension of α=168.47A, b= 50.66A, c=53.96A, β=104.22°. The asymmetric unit is expected to contain one molecule with solvent content of 51.3%.

关 键 词：变形链球菌 龋齿 Smu.776 蛋白晶体学 

分 类 号：Q51[生物学—生物化学] O72[理学—晶体学]