Nickel Metabolism in Helicobacter pylori

幽门螺杆菌中的镍代谢

• 批准号: 6872172
• 负责人: ROBERT J. MAIER
• 金额: $ 25.76万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-15 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6872172
• 关键词: Helicobacter; bacterial genetics; bacterial proteins; binding proteins; genetic transcription; guanosinetriphosphatases; laboratory rabbit; matrix assisted laser desorption ionization; metal metabolism; microarray technology; nickel; protein protein interaction; proteomics; site directed mutagenesis; tissue /cell culture

DESCRIPTION (provided by applicant): Helicobacter pyori is a spiral bacterium that colonizes the gastric mucosa of humans, leading to a variety of gastric diseases that include peptic ulcers, chronic gastritis, mucosal-associated lymphomas, and adenocarcinomas of the lower stomach and duodenum. Two nickel-containing enzymes, urease and hydrogenase, are important for the bacterium's mucosal-colonizing abilities. The goal proposed here is to understand the nickel sequestering, storage, metabolizing and metalloregulatory steps involved in the synthesis/maturation of the two nickel-containing enzymes. From studies with other organisms, the sequence-identified accessory proteins (encoded by ure and hyp genes) would be expected to form nickel sequestering and energy utilizing (GTP hydrolyzing) complexes needed for maturation of the two Ni-enzymes. In the presence of nickel, these complexes facilitate mobilization of the metal into the final sink, urease or hydrogenase. From our knowledge of purified nickel binding and GTPase accessory proteins and their interactions, a sequential Ni-mobilizing transfer pathway will be proposed. The hypothesized Ni-transfer steps will be tested by mixing together selected pure accessory proteins. The roles of some specific nickel-binding proteins (predicted from the genome sequence) in nickel sequestering, homeostasis, and regulation will be addressed via targeted mutagenesis. The specific approaches to understand nickel metabolism, homeostasis, and regulation, in H. pylori will include purification of complexes that deliver nickel to the Ni-enzymes, proteomic analysis to identify proteins, and genomic analysis of transcripts that are regulated in response to nickel supplementation. Finally, gene directed mutants in proteins that are anticipated to affect the nickel nutritional status of the bacterium (i.e. nickel homeostasis) will be characterized to understand the roles of three specific (but poorly studied) nickel binding proteins. The role of a DNA binding and nickel-sensing protein (NikR) is of particular interest as it may play a global regulatory role in metal homeostasis, in turn affecting many processes of cell metabolism.

描述（由申请人提供）：pyori的螺旋细菌是一种螺旋细菌，可在人类的胃粘膜上进行，导致各种胃疾病，包括消化性溃疡，慢性胃炎，粘膜相关的淋巴瘤和下肠胃不足的胃癌。两种含镍酶，尿素酶和氢化酶，对于细菌的粘膜殖民化能力很重要。这里提出的目标是了解涉及两种含镍酶的合成/成熟的镍隔离，存储，代谢和金属调节步骤。从与其他生物的研究中，有望在两种ni-enzymes成熟所需的镍隔离和能量（GTP水解）复合物中形成镍隔离和能量（GTP水解）配合物。在存在镍的情况下，这些配合物促进了金属动员到最终的水槽，尿素酶或氢化酶。从我们对纯化的镍结合和GTPase辅助蛋白及其相互作用的了解，将提出顺序的Ni-Mobilized转移途径。假设的NI-Transfer步骤将通过将选定的纯辅助蛋白混合在一起来测试。一些特定的镍结合蛋白（根据基因组序列预测）在镍隔离，稳态和调节中的作用将通过靶向诱变来解决。幽门螺杆菌中理解镍代谢，稳态和调节的特定方法将包括纯化为ni酶提供镍的复合物，蛋白质组学分析以鉴定蛋白质，以及对响应于补充镍的响应调节的转录本的基因组分析。最后，预计将影响细菌的镍营养状况（即镍稳态）的基因定向突变体的特征是了解三种特异性（但研究良好的）镍结合蛋白的作用。 DNA结合和镍感应蛋白（NIKR）的作用特别令人感兴趣，因为它可能在金属稳态中起全球调节作用，进而影响细胞代谢的许多过程。