Membranes of the Dental Pathogen Streptococcus Mutans

牙科病原体变形链球菌的膜

基本信息

批准号：
9028943
负责人：
L. Jeannine Brady
金额：
$ 37.5万
依托单位：
UNIVERSITY OF FLORIDA
依托单位国家：
美国
项目类别：
财政年份：
1986
资助国家：
美国
起止时间：
1986-03-01 至 2020-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9028943
关键词：
Acids Address Adherence Affect Animal Model Arterial Fatty Streak Atherosclerosis Bacteria Bacterial Adhesins Bacterial Endocarditis Binding Biochemical Biogenesis Biological Biological Assay Biology C-terminal Calorimetry Carrier Proteins Cell Wall Cell membrane Cell physiology Cell surface Cells Characteristics Chemicals Chloroplasts Co-Immunoprecipitations Competence Coronary Dental Dental caries Development Disease Dissection Drug Targeting Elements Epithelial Cells Epitopes Escherichia coli Etiology Evaluation Exhibits Extracellular Protein Family Foundations Funding Future Genes Genetic Genetic Transcription Goals Gram-Positive Bacteria Guanosine Triphosphate Phosphohydrolases Health Care Costs Homologous Gene Human Immunoprecipitation In Vitro Individual Infectious Agent Integral Membrane Protein Interferometry Invaded Laboratories Lead Life Lipid Bilayers Location Mass Spectrum Analysis Measures Mediating Membrane Membrane Proteins Methodology Methods Microbial Biofilms Mitochondria Modeling Molecular Chaperones Mutation Names Operon Organism Pathogenicity Pathway interactions Phenotype Play Process Production Property Protein Secretion Protein translocation Proteins Proteomics Rattus Research Ribosomal Interaction Ribosomes Role Signal Recognition Particle Streptococcus Streptococcus mutans Stress Study models System Tail Translating Translations Virulence Virulence Factors base biophysical techniques crosslink extracellular falls improved in vivo membrane biogenesis mutant oral bacteria oral pathogen paralogous gene pathogen protein transport public health relevance signal recognition particle receptor stem stress tolerance stressor sugar targeted treatment tool uptake

项目摘要

DESCRIPTION (provided by applicant): Streptococccus mutans is a ubiquitous oral bacterium identified as a prominent etiologic agent of human dental caries. Certain strains of S. mutans have also been identified as causative agents of bacterial endocarditis, discovered within atherosclerotic plaque, and demonstrated to invade human coronary epithelial cells. The health care cost associated with dental decay stemming from S. mutans and other cariogenic organisms alone is enormous, over $64 billion annually in the USA. This project addresses membrane biogenesis and protein secretion in S. mutans. Membranes comprised of a semi-permeable lipid bilayer enclose all cells and, by dictating what can and cannot cross by virtue of proteins embedded within them, determine cellular function. S. mutans shares features common to bacterial membrane protein insertion and protein secretion systems common to the most widely studied model organism Escherichia coli, as well as to those of mitochondria and chloroplasts, but it exhibits multiple unique properties as well. For this reason it is gaining in reputation as a model organism to better understand the protein translocation machinery in other streptococci, and Gram-positive bacteria in general. All known virulence properties of S. mutans are a consequence of its membrane protein composition and/or secreted extracellular proteins. Since biological membranes are composed of ~50% proteins by mass, and these represent most known and existing drug targets, a better understanding of the membrane insertion and transport pathways of S. mutans that guide its virulence factors to their necessary locations will facilitate future targeted therapies against this and related pathogens. This projec focuses on two critical co-translational translocation pathways, the signal recognition particle (SRP) pathway found in all living cells, and the YidC insertase pathway found in bacteria/mitochondria/chloroplasts. The presence in Gram-positive bacteria of an additional SRP component called YlxM, and of dual YidC paralogs of differing function, was discovered in S. mutans. Additional components unique to S. mutans appear to exist as well. In this project, a combination of membrane proteomics, directed genetic, biochemical, and biophysical approaches, and complementary in vivo and in vitro analyses will improve the understanding of membrane protein insertion and secretion pathways of S. mutans and will identify specific membrane-localized substrates related to the pivotal virulence properties of competence development and mutacin production since secretion pathway mutants are defective in this regard. These studies are facilitated by the establishment of methodologies to purify transitionally active ribosomes from S. mutans, to assess membrane protein insertion in vivo and in vitro, and to utilize biolayer interferometry, co-immunoprecipitation, and chemical cross-linking to detect and measure interactions of membrane-localized secretion pathway components that are crucial to the transport and insertion of the substrates identified as part of this research.

描述（由申请人提供）：变形链球菌是一种普遍存在的口腔细菌，被鉴定为人类龋齿的主要病原体。变形链球菌的某些菌株也已被鉴定为细菌性心内膜炎的病原体，在动脉粥样硬化斑块中发现，并被证明可以导致细菌性心内膜炎。人类侵入冠状动脉上皮细胞，仅由变形链球菌和其他致龋生物引起的蛀牙所造成的医疗费用就非常巨大。美国每年投入 640 亿美元，解决变形链球菌的膜生物发生和蛋白质分泌问题，膜由半渗透性脂质双层组成，包围着所有细胞，并通过嵌入其中的蛋白质来决定哪些细胞可以穿过，哪些细胞不能穿过。变形链球菌具有细菌膜蛋白插入和蛋白质分泌系统的共同特征，这些特征与研究最广泛的模式生物大肠杆菌以及线粒体和叶绿体相同，但它表现出多种独特的特征。出于这个原因，它作为模型生物体而赢得了声誉，以更好地了解其他链球菌和革兰氏阳性菌中的蛋白质易位机制，变形链球菌的所有已知毒力特性都是其膜蛋白的结果。由于生物膜由约 50% 的蛋白质组成，并且这些代表了最已知和现有的药物靶标，因此可以更好地了解指导其毒力因子的变形链球菌的膜插入和运输途径。到它们的必要位置将促进未来针对这种病原体和相关病原体的靶向治疗，该项目重点关注两个关键的共翻译易位途径，即所有活细胞中发现的信号识别颗粒（SRP）途径，以及细菌/线粒体中发现的 YidC 插入酶途径。 /叶绿体中存在一种称为 YlxM 的额外 SRP 成分，以及不同功能的双 YidC 旁系同源物，这是在 S. mutans 中发现的。在该项目中，膜蛋白质组学、定向遗传、生物化学和生物物理方法以及互补的体内和体外分析的结合将提高对变形链球菌的膜蛋白插入和分泌途径的理解。将鉴定与能力发展和突变蛋白产生的关键毒力特性相关的特定膜定位底物，因为分泌途径突变体在这方面存在缺陷，通过建立纯化过渡活性核糖体的方法来促进这些研究。来自变形链球菌，评估体内和体外膜蛋白插入，并利用生物层干涉测量、免疫共沉淀和化学交联来检测和测量对于运输和转运至关重要的膜局部分泌途径组分的相互作用。插入作为本研究一部分的底物。