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: 8662559
• 负责人: Rebecca A Splain
• 金额: $ 1.73万
• 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 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8662559
• 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（由申请方提供）：羊毛硫抗生素是核糖体产生的、经后修饰的具有抗生素活性的肽天然产物。许多通过靶向细菌肽聚糖合成中的高度保守步骤和/或破坏细胞壁和质膜而表现出独特的作用模式。鉴于这些结构对细胞活力的重要性，值得注意的是，羊毛硫抗生素似乎避开了典型的耐药途径。因此，它们对病原体如耐甲氧西林金黄色葡萄球菌（MRSA）和耐万古霉素肠球菌（VRE）仍然有效。由于抗菌药物耐药性对人类健康的威胁越来越大，羊毛硫抗生素作为感染的潜在治疗方法受到越来越多的考虑。羊毛硫抗生素的特征在于存在羊毛硫醚（Lan）和甲基羊毛硫醚（MeLan）环。这些不寻常的结构特征来自前体肽的翻译后酶促修饰。存在于前体肽中的丝氨酸和苏氨酸残基的酶促脱水分别产生脱氢丙氨酸和脱氢丁酸部分。半胱氨酸残基与脱水残基的Michael型加成产生独特的Lan和MeLan环。在某些系统中，单一的双功能酶（LanM）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lantibiotic机制以产生具有改善的治疗潜力的化合物提供了一个显著的机会。随着基因组信息的日益普及， 是新发现的羊毛硫抗生素基因簇的爆炸。更有趣的发现之一是一类双组分羊毛硫抗生素，它将细胞靶向与抗菌活性分离。例如，卤度霉素的两个单位（Hal <$和Hal <$）协同作用以实现针对一系列革兰氏阳性生物体的纳摩尔活性。Hal <$被提议结合肽聚糖前体脂质II，导致Hal <$的募集、孔形成和膜破坏。然而，缺乏导致卤度拉星有效生物活性的相互作用的分子细节。因此，该提案的长期目标是建立双组分硫醚抗生素的作用模式，并利用该知识来产生改进的硫醚抗生素。为此，将对产生卤度拉辛的LanM酶进行工程改造，以产生能够从化学合成的线性肽产生类似物的组成型活性羊毛硫抗生素合成酶。这种方法将允许纳入非自然特征，这将扩大化学空间，超出自然界的范围。将对野生型卤度拉辛和新的类似物进行评估，以揭示增强（或降解）卤度拉辛与其靶点之间结合的化学特征。本工作的结果将有助于从机理上理解羊毛硫抗生素的生物活性，为开发新的抗菌化合物提供指导。