CAJ | 학술논문

变形链球菌(Streptococcus mutans)是最主要的龋齿致病菌,其基因Smu.260编码一个约23 ku(200个氨基酸)的蛋白质.Smu.260的DNA片段被克隆到表达载体pET28a后在大肠杆菌BL21(DE3)菌株中表达得到很好的产量.产物smu.260蛋白通过Ni2+亲和柱和分子筛两步法纯化,并发现纯化后的蛋白以两种形式存在,二聚体(约46 ku)和四聚体,前者呈亮黄色,后者无色.采用悬滴气象扩散法得到了二聚体形式的晶体.晶体的x射线衍射分辨率达到23 A,晶体属正交空间群P212121,晶格参数为a=89.88 A,6=90.91 A,c=105.17 A.晶胞不对称单元内估计含有一个二聚体,溶剂含量为53%.
변형련구균(Streptococcus mutans)시최주요적우치치병균,기기인Smu.260편마일개약23 ku(200개안기산)적단백질.Smu.260적DNA편단피극륭도표체재체pET28a후재대장간균BL21(DE3)균주중표체득도흔호적산량.산물smu.260단백통과Ni2+친화주화분자사량보법순화,병발현순화후적단백이량충형식존재,이취체(약46 ku)화사취체,전자정량황색,후자무색.채용현적기상확산법득도료이취체형식적정체.정체적x사선연사분변솔체도23 A,정체속정교공간군P212121,정격삼수위a=89.88 A,6=90.91 A,c=105.17 A.정포불대칭단원내고계함유일개이취체,용제함량위53%.
Smu. 260 encodes a putative protein of 200 residues in Streptococcus mutans, a primary pathogen for human dental caries. Smu. 260 was cloned into expression vector pET28a and expressed in good amount trom the E. coli strain BL21 (DE3). Smu.260 protein was purified to homogeneity in a two-step procedure of Ni2+ chelating and size exclusion chromatography. The purified protein exists in two forms, a dimer form about 46 ku with yellow color and a tetramer form without apparent color. Crystals were obtained from the dimer protein by hanging-drop vapor-diffusion method. The crystals diffracted to about 2.3 A resolution and belong to orthorhombic space group P212121 with cell dimensions of a = 89.88A, b = 90.91 A, c = 105.17 A. The asymmetric unit is expected to contain two dimers with solvent content of 53%.