...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >HELIX PACKING IN THE SUCROSE PERMEASE OF ESCHERICHIA COLI - PROPERTIES OF ENGINEERED CHARGE PAIRS BETWEEN HELICES VII AND XI
【24h】

HELIX PACKING IN THE SUCROSE PERMEASE OF ESCHERICHIA COLI - PROPERTIES OF ENGINEERED CHARGE PAIRS BETWEEN HELICES VII AND XI

机译：螺旋在大肠杆菌中的蔗糖透膜渗透-VII和XI之间的电荷电荷对的性质。

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Of four putative intramembrane charge pairs in lactose permease, only three are conserved in the homologous sucrose permease of Escherichia coli [Bockmann, J., Heuel, H., and Lengeler, J. W. (1992) Mol. Gen. Genet. 235, 22-32]. The missing charge pair was introduced into wild-type sucrose permease by site-directed mutagenesis of Asn234 (helix VII) and Ser356 (helix XI). Individual replacement of either residue with a charged amino acid abolishes active sucrose transport with the exception of the Asn234-->Asp mutant. However, simultaneous replacement of Asn234 with Asp or Glu and Ser356 with Arg or Lys results in high activity. Thus, an acidic residue at position 234 rescues the activity of the Ser356-->Arg or Ser356-->Lys mutant, and a basic residue at position 356 rescues the activity of the Asn234-->Glu mutant. Furthermore, when expressed at a relatively low rate, the double mutant Asn234-->Asp/Ser356-->Arg is present in the membrane in a significantly greater amount than wild-type, suggesting that the charge pair improves insertion of sucrose permease into the membrane. The results indicate that helices VII and XI of sucrose permease are in close proximity and that a charge pair interaction can be established between residues 234 (helix VII) and 356 (helix XI). However, interchange of the acidic residue at position 234 with the basic residue at position 356 abolishes sucrose transport. Clearly, therefore, the interaction between the engineered residues in sucrose permease is more complex than the corresponding Asp237-Lys358 interaction in lactose permease where reversal of the charge pair has little or no effect on activity [Sahin-Toth, M., Dunten, R. L., Gonzalez, A., and Kaback, H. R. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 10547-10551]. [References: 37]
机译：乳糖通透酶中的四个假定的膜内电荷对中，在大肠杆菌的同源蔗糖通透酶中只有三个是保守的[Bockmann，J.，Heuel，H。和Lengeller，J.W。（1992）Mol.Biol.215：403-10]。 Gent将军。 235，22-32]。通过定点诱变Asn234（螺旋VII）和Ser356（螺旋XI）将缺失的电荷对引入野生型蔗糖通透酶。除Asn234-> Asp突变体外，用带电荷的氨基酸单独替换任一残基都消除了活性蔗糖转运。但是，同时用Asp或Glu替换Asn234和用Arg或Lys替换Ser356导致高活性。因此，第234位的酸性残基可以挽救Ser356-> Arg或Ser356-> Lys突变体的活性，而第356位的碱性残基则可以挽救Asn234-> Glu突变体的活性。此外，当以相对较低的速率表达时，双突变体Asn234-> Asp / Ser356-> Arg的存在量明显大于野生型，这表明电荷对可改善蔗糖通透酶向蔗糖中的插入膜。结果表明，蔗糖通透酶的螺旋VII和XI非常接近，并且可以在残基234（螺旋VII）和356（螺旋XI）之间建立电荷对相互作用。然而，在234位的酸性残基与在356位的碱性残基的交换消除了蔗糖的转运。因此，显然，蔗糖通透酶中工程残基之间的相互作用比乳糖通透酶中相应的Asp237-Lys358相互作用复杂，后者的电荷对的逆转对活性几乎没有影响[Sahin-Toth，M.，Dunten，RL ，Gonzalez，A.和Kaback，HR（1992）Proc。 Natl。学院科学U.S.A. 89，10547-10551]。 [参考：37]

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