Understanding the molecular determinants and regulation of toxin activity in bacteria

了解细菌毒素活性的分子决定因素和调节

• 批准号: 1817621
• 负责人: Rebecca Page
• 金额: $ 75万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1817621&HistoricalAwards=false
• 关键词: Understanding; molecular; determinants; regulation; toxin

Research on biofilms, bacterial communities that coat our teeth when we sleep, has been ongoing for decades. However, even today, the only certain way to remove biofilms is by mechanical force, i.e. a toothbrush. While brushing teeth is routine, removal of biofilms from ships, pipes, medical devices etc., is exceedingly difficult. Formation of biofilms is one of the major survival mechanisms utilized by bacteria, but knowledge of how it occurs is rudimentary. Bacterial persisters, a genetically identical sub-population of quiescent cells that express protein toxins and exhibit multidrug tolerance, are at the core of biofilm formation and in enabling bacteria adapt to changing environmental conditions. Gene pairs known as toxin-antitoxin (TA) systems have emerged as key components of this adaptation process. This project will determine how toxins block bacterial growth by discovering how they inactivate substrates, how they are inhibited by antitoxins and how bacteria remove toxins in order to exit persistence. In addition to helping discover novel approaches for controlling biofilms, the project will provide research training opportunities for students and STEM education opportunities for high school students through implementation of the Protein Science Workshop in the UA BIOTECH outreach project.Many TA toxins, including MqsR, the focus of this proposal, are ribonucleases (RNases). In order to control biofilm formation, an understanding of how RNase toxins regulate bacterial growth and arrest must be obtained. The research will determine how MqsR recognizes and cleaves mRNA substrates. Preliminary data suggest that this information will lead to a novel mechanism used by RNases to digest mRNA. The project will also identify how antitoxin MqsA inhibits MqsR activity, facilitating development of new approaches for toxin inhibition/modulation. Finally, the molecular determinants that direct MqsA and MqsR proteolysis and turnover in bacteria will be determined. These will define protein recognition sites that can be used to control TA turnover in cells, and provide new insights into the mechanisms used by bacterial proteases to recognize their endogenous substrates. An integrated structural, biochemical and cellular approach will be utilized to address these fundamental questions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

几十年来一直在进行生物膜，生物膜，细菌群落覆盖牙齿的细菌群落。但是，即使在今天，去除生物膜的唯一某种方法是通过机械力，即牙刷。虽然刷牙是常规的，但从船只，管道，医疗设备等中去除生物膜，这是非常困难的。生物膜的形成是细菌使用的主要生存机制之一，但了解其发生的知识是基本的。细菌持久性是一种表达蛋白质毒素并表现出多药耐受性的静态细胞的遗传相同的亚群，是生物膜形成的核心，并使细菌适应不断变化的环境条件。称为毒素 - 抗毒素（TA）系统的基因对已成为这种适应过程的关键组成部分。该项目将通过发现如何灭活底物，如何被抗毒素抑制以及细菌如何去除毒素以消除持久性来确定毒素如何阻断细菌的生长。除了帮助发现控制生物膜的新颖方法外，该项目还将通过在UA Biotech外展项目中实施蛋白质科学研讨会为学生和STEM教育机会提供研究培训机会。MQSR，包括此提案的重点，包括核糖核酸酶（RNases）。为了控制生物膜的形成，必须了解RNase毒素如何调节细菌生长和停滞。该研究将确定MQSR如何识别和切割mRNA底物。初步数据表明，此信息将导致RNases用来消化mRNA的新型机制。该项目还将确定抗毒素MQSA如何抑制MQSR活性，从而促进毒素抑制/调节的新方法的发展。最后，将确定直接MQSA和MQSR蛋白水解以及细菌转移的分子决定因素。这些将定义可用于控制细胞中TA离职的蛋白质识别位点，并为细菌蛋白酶使用的机制提供新的见解，以识别其内源性底物。将利用一种综合的结构，生化和细胞方法来解决这些基本问题。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估来获得支持。