...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of bacteriology >Domain Structure, Oligomeric State, and Mutational Analysis of PpsR, the Rhodobacter sphaeroides Repressor of Photosystem Gene Expression
【24h】

Domain Structure, Oligomeric State, and Mutational Analysis of PpsR, the Rhodobacter sphaeroides Repressor of Photosystem Gene Expression

机译：域结构，寡聚态和突变的PpsR，球形红球菌阻遏物的光系统基因表达的分析。

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

The transcription factor PpsR from the facultative photoheterotrophRhodobacter sphaeroides is involved in repression of photosystem gene expression under aerobic growth conditions. We have isolated a number of spontaneous mutations as well as constructed directed mutations and deletions in ppsR. Repressor activities and the oligomeric state of the wild-type and mutant proteins were assayed. Our results suggest that the wild-type PpsR exists in cell extracts as a tetramer. Analysis of the PpsR mutants confirmed that the carboxy-terminal region of PpsR (residues 400 to 464) is involved in DNA binding. The central region of the protein (residues 150 to 400) was found to contain two PAS domains (residues 161 to 259 and 279 to 367). PAS domains are ubiquitous protein modules involved in sensory transduction as well as in protein-protein interactions. All spontaneously isolated mutations, which significantly impaired repressor activity and which mapped outside the DNA binding region, were positioned in the PAS domains. None of these, however, affected the overall oligomeric state. This implies that the conformation of the PAS domains within the tetramer is critical for repressor activity. Upstream of the first PAS domain resides a putative glutamine-rich hinge (residues 127 to 136) that connects the first PAS domain to the amino-terminal region (residues 1 to 135). The role of the amino terminus of PpsR is not obvious; however, extended deletions within this region abolish repressor activity, thus suggesting that the amino terminus is essential for structural integrity of the protein. We present a model of the domain architecture of the PpsR protein according to which PpsR is comprised of three regions: the carboxy terminus responsible for DNA binding, the central region primarily involved in protein oligomerization and possibly signal sensing, and the amino terminus of unknown function. This model may prove useful for determining the mode of PpsR action.
机译：兼性光异养球形红球菌的转录因子PpsR参与有氧生长条件下光系统基因表达的抑制。我们已经分离了 ppsR 中的许多自发突变以及构建的定向突变和缺失。测定了野生型和突变蛋白的阻遏物活性和寡聚状态。我们的结果表明野生型PpsR以四聚体形式存在于细胞提取物中。对PpsR突变体的分析证实，PpsR的羧基末端区域（残基400至464）与DNA结合有关。发现蛋白质的中央区域（残基150至400）含有两个PAS结构域（残基161至259和279至367）。 PAS结构域是涉及传感转导以及蛋白质-蛋白质相互作用的普遍存在的蛋白质模块。所有自发分离的突变都位于PAS结构域中，这些突变显着削弱了阻遏物的活性并定位在DNA结合区域之外。然而，这些都没有影响整体的低聚状态。这意味着四聚体中PAS结构域的构象对于阻遏物活性至关重要。第一PAS结构域的上游存在推定的富含谷氨酰胺的铰链（残基127至136），其将第一PAS结构域连接至氨基末端区域（残基1至135）。 PpsR的氨基末端的作用并不明显。然而，该区域内的延伸缺失消除了阻遏物活性，因此表明氨基末端对于蛋白质的结构完整性是必不可少的。我们提出了一种PpsR蛋白的结构域模型，根据该模型，PpsR由三个区域组成：负责DNA结合的羧基末端，主要参与蛋白质寡聚化和可能的信号传感的中央区域以及功能未知的氨基末端。该模型对于确定PpsR作用的模式可能有用。

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