Structure of Proteins in Cell Walls by REDOR NMR

超出所提供的空间。万古霉素通过干扰细胞壁生物合成杀死革兰氏阳性肠球菌和葡萄球菌。我们已经证明，在野生型金黄色葡萄球菌中，万古霉素与细胞壁前体的茎端结合并抑制转糖基化（聚糖链延伸）。近年来，出现了耐万古霉素肠球菌和葡萄球菌。这些细菌改变了肽聚糖结构，减少了万古霉素的结合。我们使用固态核磁共振表征了五种氟化糖肽的细胞壁复合物，这些糖肽具有增强的抗万古霉素耐药肠球菌的效力。我们从礼来公司获得了两种药物，从俄罗斯新抗生素研究所获得了两种药物，还有一种是我们自己合成的。我们首次对这些药物的结构和活性进行了关联，并确定了它们的作用方式。在下一个资助期，我们计划证明或反驳这些药物通过干扰肽聚糖生物合成过程中的模板识别来杀死万古霉素耐药肠球菌和葡萄球菌的一般假设。我们认为新的肽聚糖链必须预先排序，以适应紧密交联的三维网络，这就是现有的最近邻链被用作合成新链的模板的原因。我们将使用固态核磁共振检测各种万古霉素敏感和耐万古霉素肠球菌和葡萄球菌的全细胞中药物复合物的形成和生物合成来测试这些概念，这些生物是我们从同事-合作者P. Courvalin（法国）和H. Labischinski（德国）那里获得的。我们将使用高选择性的稳定同位素标记方案，并通过新的，专门设计的固态核磁共振实验进行检测。我们所研究的抗万古霉素耐药肠球菌和葡萄球菌的效价提高的糖肽，没有一种因为有害的副作用而被批准在美国临床使用。我们希望通过本应用中提出的工作对这些糖肽的作用模式的深入了解，将刺激对具有可耐受副作用的新型强效抗生素的研究。网站性能 ======================================== 节结束 ===========================================

EXCEED THE SPACE PROVIDED. Vancomycin kills Gram-positive enterococci and staphylococci by interfering with cell-wall biosynthesis. We have shown that in wild-type Staphylococcus aureus, vancomycin binds to the stem termini of cell-wall precursors and inhibits transglycosylation (glycan chain extension). Recently, vancomycin-resistant enterococci and staphylococci have emerged. These bacteria have altered peptidoglycan structures and reduced vancomycin binding. We have used solid-state NMR to characterize the cell-wall complexes of five fluorinated glycopeptides with improved potency against vancomycin-resistant enterococci. We obtained two of the drugs from Eli Lilly Company, two from the Cause Institute of New Antibiotics (Russia), and one we synthesized ourselves. We have correlated structure and activity for these drugs for the first time and have formulated their mode of action. In the next grant period, we plan to prove or disprove the general hypothesis that these drugs kill vancomycin-resistant enterococci and staphylococci by interfering with template recognition during peptidoglycan biosynthesis. We believe that new peptidoglycan strands must be pre-ordered to fit into a tightly cross-linked three-dimensional network, and that this is the reason that an existing nearest-neighbor strand is used as a template for the synthesis of a new strand. We will test these notions using solid-state NMR detection of drug-complex formationand biosynthesis in whole cells of a variety of vancomycin-susceptible and vancomycin-resistant enterococci and staphylococci, organisms which we have acquired from our colleague- collaborators, P. Courvalin (France) and H. Labischinski (Germany). We will use highly selective stable-isotope labeling protocols with detection by new, specially designed solid-state NMR experiments. None of the glycopeptides with improved potency against vancomycin-resistant enterococci and staphylococci that we have examined are approved for clinical use in the United States because of deleterious side effects. We are hopeful that the insights into the mode(s) of action of these glycopeptides that will result from the work proposed in this applicationwill stimulate the search for new and potent antibiotics with tolerable side effects. PERFORMANCE SITE ========================================Section End===========================================