CAJ | 학술논문

变性链球菌(Streptococcus mutans)是最主要的龋齿致病菌.其中Smu_195c为一个约10 h(86个氨基酸)的蛋白质,序列比对结果显示,它没有包含保守的结构域,功能也是未知的.为揭示其功能,在大肠杆菌BL21(DE3)中表达了N端结合了6个His的编码Smu_195c的DNA片段.通过悬滴法得到了两种不同晶系的晶体.第一种属于空间群P6122或P6522,晶格参数为a=b=62.93 (A),c=90.63 (A),γ=120°;第二种属于空间群P41212或P43212,晶格参数为a=b=57.97 (A),c=103.51 (A).N端带有His的蛋白质长出的晶体属于第一种,而切掉N端的6个His后的蛋白质长出的晶体两种都有.
변성련구균(Streptococcus mutans)시최주요적우치치병균.기중Smu_195c위일개약10 h(86개안기산)적단백질,서렬비대결과현시,타몰유포함보수적결구역,공능야시미지적.위게시기공능,재대장간균BL21(DE3)중표체료N단결합료6개His적편마Smu_195c적DNA편단.통과현적법득도료량충불동정계적정체.제일충속우공간군P6122혹P6522,정격삼수위a=b=62.93 (A),c=90.63 (A),γ=120°;제이충속우공간군P41212혹P43212,정격삼수위a=b=57.97 (A),c=103.51 (A).N단대유His적단백질장출적정체속우제일충,이절도N단적6개His후적단백질장출적정체량충도유.
Smu_195c is a protein with 86 amino acids in Streptococcus mutans, a primary pathogen for human dental caries. The specific function of Smu_195c is still unknown and there are no conserved domains in it. In order to find out its function, the gene encodes Smu_195c was cloned and expressed in E. coli as N-terminally 6*His tagged recombinant protein. Two crystal forms were obtained by the hanging drop method. Form Ⅰ belongs to space group P6122 or P6522 with the unit cell parameters a = b = 62.93 (A), c= 90.63 (A), γ=120° and form Ⅱ belongs to the space group P41212 or P43212 with the unit cell parameters a =b=57.97 (A), c = 103.51 (A).Crystals from the protein with His-tag belong to form Ⅰ, however, crystals from the protein without His-tag belong to both.