CAJ | 학술논문

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 (A),晶体属单斜空间群C2,晶格参数为a=168.47 (A),b=50.66 (A),c=53.96 (A),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%.
변형련구균smu.776기인편마일단함유385개안기산적단백질,기공능가능위의뢰우선감갑류안산적갑기전이매.smu.776적DNA편단피극륭도표체재체pET28a후,재대장간균BL21(DE3)균주중과량표체득도흔호적산량.산물Smu.776단백통과Ni2+친화주화분자사주층석량보득도순화.채용현적기상확산법득도료Smu.776단백적정체.X사선연사분변솔체도2.0 (A),정체속단사공간군C2,정격삼수위a=168.47 (A),b=50.66 (A),c=53.96 (A),β=104.22°.매개최소불대칭단원내함유일개단백질분자,용제함량위51.3%.
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. coli strain BL21 (DE3). Smu.776 protein was purified to homogeneity in a two-step procedure ofNi2+ chelating and size exclusion chromatography. Crystals were obtained by hanging-drop vapor diffusion method and diffracted to 2.0 (A) resolution.The crystal belongs to orthorhombic space group C2 with cell dimension of a=168.47 (A), b= 50.66 (A), c=53.96 (A), β=104.22°. The asymmetric unit is expected to contain one molecule with solvent content of 51.3%.