...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of bacteriology >Expression of a Streptococcus mutans glucosyltransferase gene in Escherichia coli.
【24h】

Expression of a Streptococcus mutans glucosyltransferase gene in Escherichia coli.

机译：变形链球菌葡糖基转移酶基因在大肠杆菌中的表达。

获取原文
   

获取外文期刊封面封底 >>

       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Chromosomal DNA from Streptococcus mutans strain UAB90 (serotype c) was cloned into Escherichia coli K-12. The clone bank was screened for any sucrose-hydrolyzing activity by selection for growth on raffinose in the presence of isopropyl-beta-D-thiogalactoside. A clone expressing an S. mutans glucosyltransferase was identified. The S. mutans DNA encoding this enzyme is a 1.73-kilobase fragment cloned into the HindIII site of plasmid pBR322. We designated the gene gtfA. The plasmid-encoded gtfA enzyme, a 55,000-molecular-weight protein, is synthesized at 40% the level of pBR322-encoded beta-lactamase in E. coli minicells. Using sucrose as substrate, the gtfA enzyme catalyzes the formation of fructose and a glucan with an apparent molecular weight of 1,500. We detected the gtfA protein in S. mutans cells with antibody raised against the cloned gtfA enzyme. Immunologically identical gtfA protein appears to be present in S. mutans cells of serotypes c, e, and f, and a cross-reacting protein was made by serotype b cells. Proteins from serotype a, g, and d S. mutans cells did not react with antibody to gtfA enzyme. The gtfA activity was present in the periplasmic space of E. coli clones, since 15% of the total gtfA activity was released by cold osmotic shock and the clones were able to grow on sucrose as sole carbon source.
机译：将来自变形链球菌UAB90株（血清型c）的染色体DNA克隆到大肠杆菌K-12中。通过选择在异丙基-β-D-硫代半乳糖苷存在下在棉子糖上的生长来筛选克隆库的任何蔗糖水解活性。鉴定了表达变形链球菌葡糖基转移酶的克隆。编码该酶的变形链球菌DNA是克隆到质粒pBR322的HindIII位点的1.73个碱基的片段。我们将基因命名为gtfA。质粒编码的gtfA酶（一种55,000分子量的蛋白质）在大肠杆菌小细胞中以pBR322编码的β-内酰胺酶水平的40％合成。使用蔗糖作为底物，gtfA酶催化果糖和表观分子量为1,500的葡聚糖的形成。我们用针对克隆的gtfA酶的抗体在变形链球菌细胞中检测到gtfA蛋白。免疫学上相同的gtfA蛋白似乎存在于血清型c，e和f的变形链球菌细胞中，并且由血清型b细胞产生了交叉反应蛋白。来自血清型a，g和d。变形链球菌的蛋白质不会与gtfA酶的抗体反应。 gtfA活性存在于大肠杆菌克隆的周质空间中，因为总gtfA活性的15％是通过冷渗透休克释放的，并且这些克隆能够在蔗糖上作为唯一碳源生长。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号