Zinc dependent conformational changes in AdcR and their impact on DNA binding

AdcR 中锌依赖性构象变化及其对 DNA 结合的影响

• 批准号: 10469718
• 负责人: Joseph P Emerson
• 金额: $ 30.89万
• 依托单位: MISSISSIPPI STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-29 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10469718
• 关键词: Adopted; Affinity; Amino Acids; Anaerobic Bacteria; Binding; Binding Sites; Centers of Research Excellence; Chemical Agents; Chemicals; DNA; DNA Binding; Event; Growth; Homeostasis; Human; Ions; Location; Metals; Micronutrients; Molecular Conformation; Mutation; Nutrient; Organism; Positioning Attribute; Process; Promoter Regions; Proteins; Series; Side; Site; Streptococcus pneumoniae; Structure; System; Thermodynamics; Transition Elements; Upper respiratory tract; Virulence; Water; Zinc; pathogen; targeted treatment; therapeutic development; transcription factor

Streptococcus pneumoniae is a Gram-positive, facultative anaerobic bacteria that colonizes in the upper respiratory tract of most humans. Pathogens like S. pneumoniae rely on their host to provide all nutrients for growth, which includes several transition metal ions. Zinc(II) ions are required micronutrients for all living systems. The intracellular Zn2+ concentration in S. pneumoniae is regulated by two transcription factors (TFs). These proteins, termed AdcR and SczA, are known to bind Zn2+ ions with high affinity. In both proteins, the zinc(II) binding events induce a structural change in the protein that affords a dramatic increase in the affinity of these Zn-TFs for their specific DNA promotor regions. It is this process that regulates a series of proteins responsible for Zn2+ homeostasis within S. pneumoniae. The chemical equilibria between Zn2+, TFs, and DNA are attractive targets for therapeutic agent development, where impacting S. pneumoniae’s ability to adapt to new locations within a host can directly impact its virulence. AdcR binds two Zn2+ ions in its metal binding domain, and this binding site is stabilized through a series of intramolecular interactions between an unstructured loop in the protein. Specifically, site 1 is a coordinatively saturated tetrahedral site, where all four positions are coordinated through amino-acid side chain residues. Site 2 also adopts a tetrahedral coordination mode, however one of these sites is occupied by a water molecule, which provides an opportunity to disrupt this system. The central hypothesis associated with this proposal is that zinc(II) binding induces an organization of a dynamic loop in AdcR (Lys22 to Ser38), which locks the protein into a favorable DNA binding conformation. Perturbations to the structure of this loop by mutation (aim 1) or chemical agents (aim 2) can impact the Zn2AdcR structure significantly leading to changes in the thermodynamics of Zn2AdcR/DNA binding.

肺炎链球菌是一种革兰氏阳性的兼性厌氧菌细菌，在上呼吸道中定居 大多数人的区域。像肺炎链球菌这样的病原体依靠宿主为生长提供所有营养 包括几种过渡金属离子。对于所有生物系统，锌（II）离子是必需的。细胞内 肺炎链球菌中的Zn2+浓度受两个转录因子（TF）调节。这些蛋白质称为ADCR， 已知SCZA结合具有高亲和力的Zn2+离子。在这两种蛋白质中，锌（II）结合事件诱导结构 这些Zn-TF对其特异性DNA启动子的亲和力的变化，可显着增加 地区。正是这一过程调节了一系列负责肺炎链球菌内Zn2+稳态的蛋白质。 Zn2+，TFS和DNA之间的化学等效性是热剂发展的有吸引力的靶标，其中 影响肺炎链球菌适应宿主内新位置的能力可以直接影响其病毒。 ADCR在其金属结合结构域中结合了两个Zn2+离子，并且该结合位点通过一系列结合位点稳定 蛋白质中非结构化环之间的分子内相互作用。具体而言，站点1是协调的 饱和四面体部位，所有四个位置均通过氨基酸侧链保留协调。网站2也 采用四面体协调模式，但是这些位点之一被水分子占据 破坏该系统的机会。与该提议相关的中心假设是锌（II）结合 在ADCR中诱导动态循环的组织（LYS22至Ser38），该组织将蛋白质锁定在有利的DNA中 约束会议。通过突变（AIM 1）或化学剂（AIM 2）对该环的结构扰动可以 影响ZN2ADCR结构显着导致Zn2ADCR/DNA结合的热力学变化。