Novel Approaches to the Total Chemical Synthesis of Lasso Peptides as a Scaffold

套索肽作为支架的全化学合成新方法

• 批准号: 8868928
• 负责人: STEPHEN B.H. KENT
• 金额: $ 19.75万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-13 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8868928
• 关键词: Amides; Amino Acid Sequence; Amino Acids; Anabolism; Anti-Bacterial Agents; Antiviral Agents; Architecture; Aspartic Acid; Biological; Biological Assay; Biological Factors; C-terminal; Chemicals; Chemistry; Chicago; Crystallography; Development; Dissection; Distal; Engineering; Enzymes; Glutamic Acid; Gram-Negative Bacteria; Grant; Health; Laboratories; Lactams; Lasso; Ligation; Link; MccJ25; Mediating; Methods; Molecular Conformation; N-terminal; Nature; Peptide Hydrolases; Peptide Synthesis; Peptides; Physiological; Proteins; Reporting; Resistance; Roentgen Rays; Route; Side; Solutions; Structure; Structure-Activity Relationship; Universities; Untranslated RNA; Work; analog; analytical method; antimicrobial drug; aqueous; base; chemical synthesis; covalent bond; desulfurization; novel; novel strategies; pathogenic bacteria; peptide structure; polypeptide; protein aminoacid sequence; receptor; scaffold; success; synthetic peptide; thioester

DESCRIPTION (provided by applicant): In this exploratory grant we will systematically develop the first total chemical synthesis of lasso peptides of native structure. Lasso peptides are ribosomally synthesized bacterial natural products that have a broad spectrum of biological activities as antimicrobial or antiviral agents, and as potent receptor antagonists. Lasso peptides isolated from nature have ~20 amino acids and have a unique folded structure that is essential for their stability and for full biological activity. This folded structure has a macrolactam ring between the N-terminal amino acid and the side chain carboxyl of a glutamic acid or aspartic acid residue; the C-terminal linear peptide segment is threaded through this ring. The challenge in total chemical synthesis of lasso peptides is forming this threaded structure. Although the biosynthesis of lasso peptides is quite well understood and can be used to engineer novel sequences, to date there has been no successful total chemical synthesis of a lasso peptide of native folded structure. Here we describe novel approaches to the synthesis of lasso peptides. The synthetic strategies draw on the broad range of cutting edge synthetic and analytical methods in this laboratory, and are prioritized in order of increasing synthetic complexity to provide for versatile implementation of alternatives if/when synthetic obstacles are encountered. The proposed routes are novel extensions of the thioester-mediated, amide-forming native chemical ligation methods developed in this laboratory, used in combination with our extensive expertise in peptide synthetic methods. The folded structures of our synthetic products will be unambiguously determined by established NMR and mass spectrometric methods, and by the racemic protein crystallography method recently pioneered in this laboratory for the determination of unknown Xray structures. All synthetic products will be screened against a panel of pathogenic bacteria. Successful total chemical synthesis of lasso peptides will enable the systematic dissection of the structure-function relationships in this important class of natura products and will enable the use of a much wider range of building blocks for the exploitation of the lasso peptide scaffold in the development of novel antibacterials.

描述（由申请人提供）：在这项探索性资助中，我们将系统地开发天然结构的套索肽的第一个全化学合成。Lasso肽是细菌核糖体合成的天然产物，具有广谱的抗微生物或抗病毒剂的生物活性，并作为有效的受体拮抗剂。套索肽 从自然界中分离的具有约20个氨基酸，并且具有对其稳定性和完全生物活性至关重要的独特折叠结构。该折叠结构在N-末端氨基酸和谷氨酸或天冬氨酸残基的侧链羧基之间具有大环内酰胺环; C-末端线性肽段穿过该环。套索肽的全化学合成的挑战是形成这种螺纹结构。尽管套索肽的生物合成已被很好地理解并且可用于工程化新序列，但迄今为止还没有天然折叠结构的套索肽的成功的全化学合成。在这里，我们描述了新的方法来合成套索肽。综合战略借鉴了本实验室广泛的最先进的综合和分析方法，并按照综合复杂性的增加顺序排列优先次序，以便在遇到综合障碍时提供替代品的多功能实施。建议的路线是新的扩展硫酯介导的，酰胺形成本实验室开发的天然化学连接方法，结合我们在肽合成方法的广泛专业知识。我们的合成产品的折叠结构将明确确定的NMR和质谱方法，并通过外消旋蛋白质晶体学方法最近在这个实验室开创了未知的X射线结构的测定。所有合成产品都将针对一组致病菌进行筛选。套索肽的成功的全化学合成将使得能够系统地剖析这类重要的天然产物中的结构-功能关系，并且将使得能够在开发新型抗菌剂中使用更广泛的构建块来开发套索肽支架。