Bridge Helix Function in RNA Polymerase Catalysis

RNA聚合酶是一种细胞复印机，根据需要从遗传物质转录出基因的临时副本(转录本)。在后基因组时代，我们知道存储在我们的遗传物质中的信息含量，但对于这些信息在不同生物条件下是如何读出的，我们仍然有很多需要了解的；RNA聚合酶在这些分子决策事件中起着至关重要的作用。尽管在过去的十年里，关于它们的分子结构的重要信息已经出现(这一成就在2007年被授予罗杰·科恩伯格教授诺贝尔奖)，但许多重要的问题仍然没有得到回答。RNA聚合酶最好被想象成移动的分子机器，沿着DNA爬行来产生转录本。为了做到这一点，RNA聚合酶将复杂的内部运动与精确定义的化学活性(在其催化中心合成转录本)结合起来。在以前的工作中，我们确定了位于RNA聚合酶核心的纳米机械元件？桥螺旋？的关键作用。桥式螺旋通过改变两个主要分子铰链的设置来实现其功能。这些分子铰链的扭结改变了催化位点内其他结构的排列，以协调它们在转录过程的不同阶段的位置。围绕其中一个分子铰链BH-HN功能的分子事件是拟议研究的重点。BH-HN特别令人兴奋，因为它的存在是最近才发现的，因此有可能导致我们思考RNA聚合酶机制和功能的方式发生重大变化。我们将使用新开发的机器人工具进行传统技术无法实现的研究。这项工作不仅具有深厚的科学价值，而且可能在未来产生医学应用。已知几种用于对抗病原菌的抗生素会干扰RNA聚合酶的分子机制。在我们最近的工作中，我们发现BH-HN似乎在少数细菌中永久激活，包括一种与食物中毒有关的紧急病原体和另一种在东亚具有毁灭性致命影响的病原体。这些例子非常清楚地表明，基础科学的成果往往会在现实世界中产生洞察力和应用，从而有很大机会改善生活质量和提供医疗保健。

RNA polymerases are the cellular photocopiers transcribe a temporary copy of a gene ( a transcript ) from the genetic material as required. In the post-genomic era we know the information content stored in our genetic material, but still have lot to learn about the way this information is read out under different biological conditions; RNA polymerases are critically involved in these molecular decision-making events. Although important information about their molecular structure has emerged during the last decade (an achievement which was rewarded with a Nobel Prize to Prof. Roger Kornberg in 2007), many important questions remain unanswered. RNA polymerases can best be imagined as mobile molecular machines that crawl along the DNA to produce their transcripts. In order to do this, RNA polymerases combine complex internal motions with a precisely defined chemical activity (synthesis of the transcript in its catalytic center). In previous work we identified a key role for a nanomechanical element, the ?Bridge Helix?, located at the core of RNA polymerase. The Bridge Helix carries out its function through changing the settings of two major molecular hinges. Kinking of these molecular hinges changes the arrangement of other structures within the catalytically site to cocordinate their position at various stages of the transcription process. The molecular events surrounding the function of one of these molecular hinges, BH-HN, is the focus of the proposed research. BH-HN is particularly exciting because its existence was only recently discovered and therefore has the potential to cause a significant change in the way we are thinking about RNA polymerase mechanisms and function. We will use newly developed robotic tools to carry out studies in a way that would not be feasible using conventional techniques.This work is not only of profound scientific interest, but may also give rise to medical applications in the future. Several antibiotics used to fight pathogenic bacteria are known to interfere with the molecular mechanisms of RNA polymerase. In our most recent work we showed that BH-HN appears to be permanently activated in a small number of bacteria, including an emergent pathogen involved in food poisoning and another pathogen with devastatingly lethal effects in East Asia. These examples demonstrate very clearly that results from fundamental sciences often give rise to insights and applications in the real world that have a substantial chance of improving the quality of life and the provision of healthcare.