PGT Inhibitors Mapped From a Tunicamycin Blueprint

根据衣霉素蓝图绘制的 PGT 抑制剂

• 批准号: 8508008
• 负责人: Barbara Imperiali
• 金额: $ 23.54万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-02-01 至 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8508008
• 关键词: Acids; Active Sites; Address; Amino Acids; Anabolism; Animals; Antibiotics; Binding; Biological Assay; Biological Factors; Boston; Campylobacter jejuni; Carbohydrates; Cell Line; Cell Survival; Cell surface; Chemical Agents; Chemical Structure; Chemicals; Collaborations; Commit; Complex; Detection; Dolichol; Enzyme Inhibition; Enzymes; Evaluation; Family; Feedback; Genetic; Glycoconjugates; Glycoproteins; Goals; Helicobacter; Homologous Gene; Human; In Vitro; Inhibitory Concentration 50; Label; Lead; Link; Lipopolysaccharides; Location; Logic; Mammalian Cell; Maps; Membrane; Metabolic; Methods; Microbial Physiology; Molecular; N-terminal; Nature; Nucleosides; Organism; Pathogenicity; Pathway interactions; Phase; Play; Polysaccharides; Printing; Process; Proteins; Radioactivity; Reaction; Research; Roentgen Rays; Role; Saccharomyces cerevisiae; Salmonella enterica; Selenomethionine; Site; Specificity; Staging; Structure; Substrate Specificity; System; Teichoic Acids; Testing; Toxic effect; Transferase; Tunicamycin; Universities; Uridine Diphosphate Sugars; Work; X-Ray Crystallography; Yeasts; analog; base; cross reactivity; design; enzyme activity; glycoprotein biosynthesis; improved; inhibitor/antagonist; inorganic phosphate; insight; microbial; microorganism interaction; mimetics; nucleobase; pathogen; professor; programs; public health relevance; scaffold; small molecule; sugar; tool; undecaprenyl phosphate

DESCRIPTION (provided by applicant): Phosphoglycosyl transferases (PGTs) are membrane-bound enzymes, which catalyze the transfer of a phosphoglycosyl group from an activated UDP-sugar donor to a polyprenylphosphate acceptor. PGT-catalyzed reactions afford amphiphilic polyprenyldiphosphate-linked carbohydrates, thereby committing glycan assembly processes to a location at the membrane interface. PGTs are specific for the identity of the UDP-sugar that they act on, which defines the nature of the transferred phosphoglycosyl group. These enzymes are most commonly involved in an essential early step that features in many glycoconjugate assembly pathways including those that lead to bacterial lipopolysaccharides and capsular polysaccharides, teichoic acids, and N- and O-linked glycoproteins. Such glycoconjugates play critical roles in the interactions of microbial pathogens with the hosts that they infect, however, there is a dearth of selective small molecule inhibitors, which can be used as tools to assess and define the significance of specific glycoconjugates in microbial physiology and to elucidate their roles in host-pathogen interactions. This research will address the critical need for new chemical agents as inhibitors for bacterial PGTs and seeks to provide selective inhibitors of diverse PGTs that act on different UDP-sugar donor substrates. In this exploratory program we will employ synergistic approaches involving inhibitor design and synthesis, X-ray based structure determination, and enzymatic analysis to develop a general method for the genesis of potent and selective bacterial PGT inhibitors. The central theme of the research approach relies on exploiting the molecular logic of the natural product nucleoside antibiotics, in particular tunicamycin, as a "blue print" for the structure-guided design and synthesis of a new family of modular chemical structures that act as selective inhibitors of PGTs. Tunicamycin is a potent bisubstrate analog inhibitor of the bacterial PGT, Wec A, which is a homolog of the yeast PGT Alg7, and also inhibits PglC-Hpu, a small PGT from H. pullorum with IC50 of 350¿30 nM. These enzymes catalyze phosphoglycosyl transfer from UDP-GlcNAc to undecaprenylphosphate thereby initiating lipopolysaccharide and N-linked glycoprotein biosynthesis in the respective organisms. Focusing first on three small PGTs from different microbial pathogens that act on diverse phosphoglycosyl donor substrates (UDP-GlcNAc, UDP-Gal and UDP-Bac) and a common undecaprenyl phosphate (UndP) acceptor, we will develop and validate tractable and modular synthetic platforms for the assembly of new inhibitors. If successful, this research will lead to a new inhibitor design approach that can be applied broadly to a large family of PGTs and to powerful chemical tools that will afford valuable new insight into the functional significance of complex glycoprotein conjugates that decorate the cell surfaces of many microbial pathogens.

描述（由申请人提供）：磷酸糖基转移酶（PGTs）是膜结合酶，催化磷酸糖基从活化的UDP-糖供体转移到聚异戊二烯磷酸受体。PGT催化的反应提供两亲性聚异戊二烯二磷酸连接的碳水化合物，从而将聚糖组装过程提交到膜界面的位置。PGTs对它们所作用的UDP-糖的身份具有特异性，这定义了转移的磷酸糖基的性质。这些酶最常参与许多糖缀合物组装途径中的重要早期步骤，包括导致细菌脂多糖和荚膜多糖、磷壁酸以及N-和O-连接糖蛋白的那些。这种糖缀合物在微生物病原体与它们感染的宿主的相互作用中起关键作用，然而，缺乏选择性小分子抑制剂，其可用作评估和定义特定糖缀合物在微生物生理学中的意义以及阐明它们在宿主-病原体相互作用中的作用的工具。这项研究将解决对新的化学试剂作为细菌PGTs抑制剂的迫切需求，并寻求提供作用于不同UDP-糖供体底物的不同PGTs的选择性抑制剂。在这个探索性的计划中，我们将采用协同的方法，包括抑制剂的设计和合成，基于X射线的结构测定，和酶分析，以开发一种通用的方法，用于产生有效的和选择性的细菌PGT抑制剂。研究方法的中心主题依赖于利用天然产物核苷抗生素，特别是衣霉素的分子逻辑，作为结构指导设计和合成新家族的模块化化学结构的“蓝图”，这些结构可作为PGTs的选择性抑制剂。衣霉素是细菌PGT的有效双底物类似物抑制剂，Wec A是酵母PGT Alg 7的同源物，也抑制来自H.鸡白痢的IC 50为350 - 30 nM。这些酶催化磷酸糖基从UDP-GlcNAc转移到十一异戊二烯基磷酸，从而在相应的生物体中启动脂多糖和N-连接糖蛋白的生物合成。首先关注来自不同微生物病原体的作用于不同磷酸糖基供体底物（UDP-GlcNAc，UDP-Gal和UDP-Bac）和共同的十一异戊二烯磷酸（UndP）受体的三种小PGTs，我们将开发和验证用于组装新抑制剂的易处理和模块化合成平台。如果成功，这项研究将导致一种新的抑制剂设计方法，可以广泛应用于一个大家族的PGTs和强大的化学工具，将提供有价值的新的洞察复杂的糖蛋白缀合物的功能意义，装饰许多微生物病原体的细胞表面。