Investigation into the antibiotic activity of the lantibiotic haloduracin

羊毛硫抗生素卤杜星的抗生素活性研究

• 批准号: 8456481
• 负责人: Rebecca A Splain
• 金额: $ 4.92万
• 依托单位: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-16 至 2015-04-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8456481
• 关键词: Amino Acids; Anabolism; Anti-Bacterial Agents; Antibiotics; Attention; Bacteria; Bacterial Drug Resistance; Bacterial Infections; Binding; Biochemical; Biological; Biological Factors; Biomedical Engineering; C-terminal; Calorimetry; Cell Wall; Cell membrane; Chemicals; Chemistry; Cleaved cell; Communicable Diseases; Complex; Cyclization; Cysteine; Dehydration; Development; Engineering; Enzymes; Exhibits; Explosion; Fluorescence; Gene Cluster; Genomics; Goals; Health; Human; In Vitro; Infection; Investigation; Knowledge; Lead; Ligase; Link; Lipids; Location; Maps; Mass Spectrum Analysis; Medicine; Membrane; Methodology; Methods; Modification; Molecular; N-terminal; NMR Spectroscopy; Names; Nature; Organism; Pathway interactions; Penicillins; Peptide Leader Sequences; Peptides; Peptidoglycan; Physiological; Post-Translational Protein Processing; Prevalence; Procedures; Process; Production; Protein Engineering; Race; Resistance; Resistance development; Serine; Structure; Structure-Activity Relationship; System; Techniques; Therapeutic; Threonine; Titrations; Tryptophan; Vancomycin resistant enterococcus; Work; World Health Organization; analog; antimicrobial; arm; bacterial resistance; cellular targeting; clinically relevant; crosslink; dehydroalanine; dehydrobutyrine; design; disorder risk; drug candidate; drug resistant bacteria; improved; lanthionine; methicillin resistant Staphylococcus aureus; muramyl-NAc-(pentapeptide)pyrophosphoryl-undecaprenol; novel; pathogen; public health relevance; research study; tool

DESCRIPTION (provided by applicant): Lantibiotics are ribosomally produced, post translationally modified peptide natural products with antibiotic activity. Many exhibit unique modes of action by targeting highly conserved steps in bacterial peptidoglycan synthesis and/or disrupting the cell wall and plasma membrane. Given the importance of these structures to cellular viability, it is noteworthy that lantibiotics appear to elude the typical resistance pathwys. Thus, they remain potent against pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Due to the increasing threat of antibacterial resistance to human health, lantibiotics have been receiving increased consideration as potential treatments for infection. Lantibiotics are characterized by the presence of lanthionine (Lan) and methyllanthionine (MeLan) rings. These unusual structural features arise from the posttranslational, enzymatic modification of precursor peptides. Enzymatic dehydration of serine and threonine residues present in the precursor peptide yield dehydroalanine and dehydrobutyrine moieties, respectively. Michael-type addition of cysteine residues to the dehydrated residues produces the distinctive Lan and MeLan rings. In some systems a single bifunctional enzyme (LanM) is responsible for both dehydration and cyclization. The brevity of the genetically encoded biosynthetic pathways provides a remarkable opportunity for reengineering the lantibiotic machinery to generate compounds with improved therapeutic potential. Facilitated by the increasing availability of genomic information, there has been an explosion of newly discovered lantibiotic gene clusters. One of the more intriguing findings is a class of two-component lantibiotics that segregate cellular targeting from antimicrobial activity. For example, the two units of haloduracin (Hal¿ and Hal¿) act in synergy to achieve nanomolar activity against a range of Gram-positive organisms. Hal¿ is proposed to bind the peptidoglycan precursor lipid II, leading to the recruitment of Hal¿, pore formation and membrane disruption. However, molecular details about the interactions that lead to the potent bioactivity of haloduracin are lacking. Thus, the long-term goal of this proposal is to establish te mode of action of two-component lantibiotics and to use that knowledge to generate improved lantibiotics. To this end, the LanM enzymes that produce haloduracin will be engineered to generate constitutively active lantibiotic synthetases capable of producing analogues from chemically synthesized linear peptides. This methodology will allow the incorporation of non-natural features that will expand the chemical space beyond that accessible to Nature. Wild-type haloduracin and new analogues will be evaluated to uncover chemical features that enhance (or degrade) binding between haloduracin and its targets. The results of this work will enhance the mechanistic understanding of lantibiotic bioactivity, which may guide the development of new antibacterial compounds.

描述(申请人提供)：抗生素是核糖体生产的，翻译后修饰的具有抗生素活性的多肽天然产品。许多细胞通过靶向细菌肽聚糖合成中高度保守的步骤和/或破坏细胞壁和质膜而显示出独特的作用模式。鉴于这些结构对细胞活性的重要性，值得注意的是，抗生素似乎避开了典型的耐药途径。因此，它们对甲氧西林耐药金黄色葡萄球菌(MRSA)和万古霉素耐药肠球菌(VRE)等病原体仍然有效。由于抗菌素耐药性对人类健康的威胁越来越大，抗生素作为潜在的感染治疗方法正受到越来越多的考虑。抗生素的特征是存在羊毛硫氨酸(LAN)和甲基羊毛硫氨酸(Melan)环。这些不寻常的结构特征源于前体多肽的翻译后酶修饰。前体多肽中的丝氨酸和苏氨酸残基的酶脱水分别产生脱氢丙氨酸和脱氢丁氨酸部分。半胱氨酸残基与脱水残基的迈克尔式加成反应产生独特的Lan环和Melan环。在一些系统中，一个单一的双功能酶(LAMM)负责脱水和环化。基因编码的生物合成途径的简洁性为重新设计抗生素机制以产生具有更好治疗潜力的化合物提供了一个极好的机会。在基因组信息日益可用的推动下，有 是新发现的抗生素基因簇的爆炸性增长。更耐人寻味的发现之一是一类双组分抗生素，它将细胞靶向与抗菌活性分开。例如，氟尿酸的两个单位(Hal？和Hal？)协同作用，以实现针对一系列革兰氏阳性菌的纳摩尔活性。Hal？被认为与肽聚糖前体脂类II结合，导致Hal？的募集、孔形成和膜破坏。然而，关于导致氟尿酸具有强大生物活性的相互作用的分子细节尚不清楚。因此，这项建议的长期目标是建立双组分抗生素的作用模式，并利用这一知识生产改进的抗生素。为此，生产氟尿酸的LAMM酶将被改造成能够从化学合成的线状多肽中产生类似物的具有构成活性的l抗生素合成酶。这一方法将允许纳入非自然特征，从而将化学空间扩展到大自然所能接触到的范围之外。将对野生型氟尿酸和新的类似物进行评估，以揭示增强(或降低)氟尿酸与其靶标之间结合的化学特征。这项工作的结果将加深对抗生素生物活性的机理认识，为开发新的抗菌化合物提供指导。