Biosynthesis, structure and function of cell wall in Streptococcus mutans

变形链球菌细胞壁的生物合成、结构和功能

• 批准号: 10379089
• 负责人: Natalia Korotkova
• 金额: $ 35.97万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-08 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10379089
• 关键词: Adherence; Affect; Anabolism; Analytical Chemistry; Antibiotics; Antimicrobial Resistance; Autolysin; Autolysis; Bacteremia; Bacteria; Biochemical; Biogenesis; Biology; Carbohydrates; Cell Wall; Cell division; Cell physiology; Cell surface; Cellular Morphology; Charge; Chemical Structure; Collaborations; Defect; Dental caries; Development; Divalent Cations; Drug Design; Drug Targeting; Enzymatic Biochemistry; Enzymes; Etiology; Future; Genetic; Glucose; Glycerol; Goals; Gram-Positive Bacteria; Human; In Vitro; Infection; Infective endocarditis; Knowledge; Lead; Light; Link; Mass Spectrum Analysis; Mechanics; Methods; Microbial Biofilms; Microscopy; Modeling; Modification; Molecular; Molecular Genetics; Molecular Structure; Morphology; NMR Spectroscopy; Oral cavity; Outcome; Outcomes Research; Pathogenesis; Pathway interactions; Peptidoglycan; Permeability; Phenotype; Phospholipase A2; Phospholipids; Play; Polysaccharides; Predisposition; Preparation; Process; Property; Proteins; Publishing; Rattus; Regulation; Reporting; Research; Resistance; Rhamnose; Role; Septal Region; Serotyping; Side; Signal Transduction; Spatial Distribution; Streptococcus; Streptococcus mutans; Streptococcus pyogenes; Structure; Surface; Techniques; Testing; Transferase; Vertebral column; Virulence; Work; antimicrobial; antimicrobial drug; base; carbohydrate biosynthesis; carbohydrate structure; cell envelope; drug development; extracellular; improved; inorganic phosphate; insight; lipoteichoic acid; mutant; nanomechanics; neutrophil; novel; novel strategies; pathogen; quorum sensing; recruit; targeted treatment; therapeutic target; therapeutically effective

The cell wall of many species of Lactobacillales consists of multiple peptidoglycan layers decorated with serotype-specific polysaccharides that are characterized by the presence of rhamnose. Streptococcus mutans is a key etiological agent of human dental caries, and has also been implicated in bacteremia and infective endocarditis. Based on the chemical structures of serotype-specific carbohydrates, S. mutans is classified into serotypes c, e, f and k with approximately 70-80% of strains found in the oral cavity classified as serotype c. The serotype c-specific carbohydrate (SCC) of S. mutans is composed of a polyrhamnose backbone with α- linked glucose side-chains. Although carbohydrate structures have been reported for all S. mutans serotypes, our recent insights into the structure of these glycopolymers indicate that the functionally important modification, glycerol phosphate, was overlooked, possibly due to its loss during the purification steps. This new finding justifies a re-examination of the chemical structures of serotype-specific carbohydrates. One of the goals of the proposed study is to determine the molecular structure of SCC isolated from S. mutans using mild, non-destructive methods. Moreover, little is known about the multienzyme processes involved in attachment of the glucose side-chains to the polyrhamnose backbone of SCC and the function of the glycerol phosphate modification in S. mutans. Our preliminary findings revealed that the glycerol phosphate modification plays important roles in S. mutans morphology, autolysis, resistance to antimicrobials and biofilm formation. We propose to identify and functionally characterize the enzymes involved in glucose side-chain attachment to polyrhamnose, and investigate the molecular mechanisms underlying the functions of glycerol phosphate modification in morphology, autolysis and biofilm formation. To accomplish our goals, we will employ streptococcal genetics, in vitro enzymology, NMR spectroscopy of polysaccharides, analytical chemistry, mass spectrometric analysis of phospholipids, and various methods of microscopy including AFM-based nanomechanics. The cell wall biosynthetic machinery is an historically preferred target for the development of novel antimicrobials. In order to validate the pathway of SCC decoration with glycerol phosphate as a potential drug target, we will determine the role of this modification in a rat caries model. Successful outcomes will guide future studies of cell wall biogenesis in other important Gram-positive bacteria and the development of novel strategies to treat S. mutans infections.

许多乳酸菌的细胞壁由多个肽聚糖层组成 用血清型特异性多糖装饰，其特征在于存在 鼠李糖。变形链球菌是人类龋齿的主要病原菌， 也与菌血症和感染性心内膜炎有关。基于化学结构 根据血清型特异性碳水化合物，变形链球菌分为血清型 c、e、f 和 k，其中 口腔中发现的大约 70-80% 的菌株被归类为血清型 c。血清型 变形链球菌的 c 特异性碳水化合物 (SCC) 由具有 α- 的多鼠李糖主链组成 连接葡萄糖侧链。尽管碳水化合物的结构已被报道为所有 对于变形链球菌血清型，我们最近对这些糖聚合物结构的了解表明 功能上重要的修饰，磷酸甘油，被忽视了，可能是由于它的 纯化步骤中的损失。这一新发现证明有必要重新检查该化学品 血清型特异性碳水化合物的结构。拟议研究的目标之一是 使用温和、非破坏性的方法确定从变形链球菌中分离出的 SCC 的分子结构 方法。此外，人们对参与附着的多酶过程知之甚少。 SCC 多鼠李糖主链的葡萄糖侧链以及甘油的功能 变形链球菌中的磷酸盐修饰。我们的初步研究结果表明，甘油 磷酸盐修饰在变形链球菌形态、自溶、抗性等方面发挥着重要作用 抗菌剂和生物膜的形成。我们建议识别并功能表征 参与葡萄糖侧链与多聚鼠李糖连接的酶，并研究 磷酸甘油修饰功能的分子机制 形态、自溶和生物膜形成。为了实现我们的目标，我们将雇用 链球菌遗传学、体外酶学、多糖核磁共振波谱、分析 化学、磷脂的质谱分析以及各种显微镜方法 包括基于 AFM 的纳米力学。细胞壁生物合成机制是一种历史悠久的生物合成机制。 开发新型抗菌药物的首选目标。为了验证该路径 以磷酸甘油作为SCC修饰的潜在药物靶点，我们将确定其作用 这种修改是在大鼠龋齿模型中进行的。成功的结果将指导未来的细胞壁研究 其他重要革兰氏阳性细菌的生物发生以及新策略的开发 治疗变形链球菌感染。