• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Molecular and Cellular Biology >A Conserved Phenylalanine of Motif IV in Superfamily 2 Helicases Is Required for Cooperative, ATP-Dependent Binding of RNA Substrates in DEAD-Box Proteins
【24h】

A Conserved Phenylalanine of Motif IV in Superfamily 2 Helicases Is Required for Cooperative, ATP-Dependent Binding of RNA Substrates in DEAD-Box Proteins

机译：超家族2解旋酶中母体IV的保守的苯丙氨酸是DEAD-Box蛋白中RNA底物的合作，ATP依赖性结合所必需的。

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

摘要

We have identified a highly conserved phenylalanine in motif IV of the DEAD-box helicases that is important for their enzymatic activities. In vivo analyses of essential proteins in yeast showed that mutants of this residue had severe growth phenotypes. Most of the mutants also were temperature sensitive, which suggested that the mutations altered the conformational stability. Intragenic suppressors of the F405L mutation in yeast Ded1 mapped close to regions of the protein involved in ATP or RNA binding in DEAD-box crystal structures, which implicated a defect at this level. In vitro experiments showed that these mutations affected ATP binding and hydrolysis as well as strand displacement activity. However, the most pronounced effect was the loss of the ATP-dependent cooperative binding of the RNA substrates. Sequence analyses and an examination of the Protein Data Bank showed that the motif IV phenylalanine is conserved among superfamily 2 helicases. The phenylalanine appears to be an anchor that maintains the rigidity of the RecA-like domain. For DEAD-box proteins, the phenylalanine also aligns a highly conserved arginine of motif VI through van der Waals and cation-π interactions, thereby helping to maintain the network of interactions that exist between the different motifs involved in ATP and RNA binding.
机译：我们已经在DEAD-box解旋酶的基序IV中鉴定出高度保守的苯丙氨酸，这对它们的酶促活性很重要。酵母中必需蛋白的体内分析表明，该残基的突变体具有严重的生长表型。大多数突变体也对温度敏感，这表明该突变改变了构象稳定性。酵母Ded1中F405L突变的基因内抑制子位于DEAD-box晶体结构中与ATP或RNA结合有关的蛋白质区域附近，这暗示了该水平的缺陷。体外实验表明，这些突变影响ATP结合和水解以及链置换活性。但是，最明显的作用是RNA底物的ATP依赖性协同结合的丧失。序列分析和对蛋白质数据库的检查表明，IV家族苯丙氨酸基序在超家族2解旋酶中是保守的。苯丙氨酸似乎是保持RecA样域刚性的锚。对于DEAD-box蛋白，苯丙氨酸还通过范德华斯和阳离子-π相互作用排列了高度保守的VI精氨酸，从而帮助维持了涉及ATP和RNA结合的不同基序之间存在的相互作用网络。

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