Structure-Function Studies of the Proton-Gated Urea Channel from H. Pylori

幽门螺杆菌质子门控尿素通道的结构功能研究

基本信息

批准号：
7556346
负责人：
HARTMUT LUECKE
金额：
$ 42.57万
依托单位：
UNIVERSITY OF CALIFORNIA-IRVINE
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-02-01 至 2013-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7556346
关键词：
Acclimatization Acids Animal Model Antibiotics Bacteria Bicarbonates Bordetella parapertussis Bacterium Buffers C-terminal Carbon Dioxide Carboxylic Acids Carcinogens Chimera organism Clarithromycin Comamonas testosteroni Country Crystallization Cytoplasm Cytoplasmic Tail Detergents Developed Countries Developing Countries Development Diffuse Diffusion Disease Docking Environment Gastric Adenocarcinoma Gastric Metaplasia Gastric mucosa Goals Growth Helicobacter Helicobacter Infections Helicobacter pylori Histidine Homologous Gene Human Hydrogen Bonding Hydrolysis In Vitro Incidence Infection Intervention Intestinal Diseases Knock-out Lactobacillus reuteri Lipids Measures Membrane Membrane Proteins Metronidazole Modeling Mutagenesis Mutation Nature Organism Paracoccus denitrificans Pathology Patients Peptic Ulcer Phase Population Preventive Proteins Proton Pump Inhibitors Protons Pseudomonas aeruginosa Resistance Resolution Risk Role Site-Directed Mutagenesis Stomach Streptococcus salivarius Streptococcus thermophilus Structure Structure-Activity Relationship Testing Thiourea Tryptophan Urea Urease Virulence Factors Work X-Ray Crystallography base carbamic acid carbonate dehydratase disorder prevention falls high throughput screening in vivo inhibitor/antagonist malignant stomach neoplasm pathogen periplasm porin prevent protonation public health relevance response small molecule solute three dimensional structure vapor

项目摘要

DESCRIPTION (provided by applicant): Infection of the gastric mucosa by Helicobacter pylori remains a worldwide problem and contributes to peptic ulcer disease and gastric cancer. Without active intervention, at least 20% of the population of developed countries will continue to be infected by this gastric pathogen. Eradication of the organism would contribute to prevention of disease. Current eradication requires triple therapy, a proton-pump inhibitor and two antibiotics given twice a day for 10 to 14 days. Resistance to either clarithromycin or metronidazole is > 20% and rising. No monotherapy is effective. Gastric infection by H. pylori depends on the expression of a channel unique to this pathogen, UreI. UreI is a proton-gated urea channel necessary for rapid access of urea to intrabacterial urease, essential for maintaining the periplasm at pH 6.1 in the acidic environment of the stomach, as low as pH 2.5, thus allowing colonization of the stomach. Expression of the channel is increased in the stomach. The channel has 193 residues with six transmembrane segments and three periplasmic regions. Mutagenesis studies have shown that the proton gating of UreI is regulated by hydrogen bonding between histidines and carboxylic acid residues in these three periplasmic regions. Obtaining a high-resolution 3-dimensional structure of this channel is the major goal of this work. This will enable understanding of the unique proton-gating mechanism of this protein and will provide a structure to which inhibitors, some of which have been discovered already, can be docked and their structure-activity relationship identified. Inhibition of this channel would be expected to result in specific and effective monotherapy for eradication of the organism and usher in an era of test and treat, rather than only treating symptomatic patients. This would provide a preventive approach to serious upper gastro-intestinal diseases, particularly gastric cancer. PUBLIC HEALTH RELEVANCE Infection of the human stomach by Helicobacter pylori remains an unresolved problem in both the West and underdeveloped countries. Infection increases the risk of developing gastric cancer about 20-fold. Current eradication therapy is cumbersome, requiring twice-a-day administration of a proton-pump inhibitor and two antibiotics. A high-resolution structure of the proton-gated urea channel, UreI, will provide a template for the development of inhibitors that will allow simple targeted monotherapy, allowing a test and treat strategy worldwide to prevent peptic ulcer disease and reduce the incidence of gastric adenocarcinoma.

描述（由申请人提供）：幽门螺杆菌对胃粘膜的感染仍然是全球问题，并导致了消化性溃疡疾病和胃癌。没有主动干预，至少有20％的发达国家将继续被这种胃病原体感染。根除生物体将有助于预防疾病。当前的根除需要三重治疗，一种质子 - 泵抑制剂和两种抗生素，每天两次进行10至14天。对克拉霉素或甲硝唑的耐药性> 20％且上升。没有单一治疗是有效的。幽门螺杆菌的胃感染取决于该病原体UREI所特有的通道的表达。 UREI是一种质子门控尿素通道，可快速进入尿素尿素尿素酶，对于在胃的酸性环境中保持pH 6.1至关重要，低至pH 2.5，因此允许胃定植。通道的表达在胃中增加。该通道有193个残基，有6个跨膜段和三个周围区域。诱变研究表明，UREI的质子门控受到这三个阴性区域中组氨酸和羧酸残基之间的氢键的调节。获得此渠道的高分辨率3维结构是这项工作的主要目标。这将使人们能够理解该蛋白质的独特质子门控机制，并将提供一种结构，其中一些已经发现的抑制剂可以停靠，并确定其结构活性关系。预计该通道的抑制作用会导致特定而有效的单一疗法消除生物体，并在测试和治疗时代使用，而不仅仅是治疗有症状的患者。这将为严重的胃肠内疾病，尤其是胃癌提供预防方法。在西方和欠发达国家，幽门螺杆菌对人类胃的公共卫生相关性感染仍然是一个尚未解决的问题。感染增加了胃癌的风险约20倍。当前的根除疗法很麻烦，需要每天两次给药质子 - 泵抑制剂和两种抗生素。质子门控尿素通道UREI的高分辨率结构将为开发抑制剂提供模板，该模板将允许简单的靶向单一疗法，允许在全球范围内进行测试和治疗策略，以防止消化性溃疡疾病并减少胃腺癌的发生率。