Chemical synthesis of novel antimicrobial peptides that target multidrug resistant bacteria

抗菌素耐药性(AMR)对医疗保健质量和生活质量造成的日益增长的威胁1-3得到了很好的证明；据预测，到2050年，每年将有1000万人死于抗菌素耐药性。4由于缺乏开发新的抗菌剂化合物，以及它们在全球医疗保健中的过度使用，这个问题更加突出。2 2000至2010年间，抗生素的药用增加了近40%。4将这一点与过去几十年没有发现的抗生素结合在一起，通过大制药公司减少或取消其抗菌素研发1，你就会对问题的规模有一个感觉。显然，这不是一个现在可以忽视、以后再解决的问题；美国和欧洲每年有5万人已知死于可治疗的细菌感染。4统计数据还告诉我们，每年有180万人死于结核病5，这确实是可以治愈的。研究和开发新的抗微生物化合物(AMCs)的必要性是显而易见的。幸运的是，在这类药用化合物的研究领域仍有许多未被触及的途径。多肽提供了一种很有希望的AMC来源；它们提供了不同的结构能力，使它们可以通过几种不同的途径杀死细菌，人们可以在微调特性的同时使它们更具成本效益。一些广为人知的抗生素属于多肽家族，如多粘菌素B6和万古霉素7。不幸的是，对这些抗生素的耐药性已经是已知的8，9，这进一步突出了将多肽作为候选抗生素进行更多研究的必要性。抗生素可以通过多种方式杀死细菌，但也许最有效的策略是针对参与基本细菌过程的酶。出现抗药性的可能性较小，因为细菌不会改变会阻碍自身生存的加工过程。众所周知，多肽与DNA过程中的一系列酶结合，并阻碍其他对生存至关重要的酶。多肽合成是在固体载体上进行的，称为固相多肽合成(SPPS)，是一个相对简单和有效的过程。在整个研究过程中，SPPS将被用于合成抗菌肽的新类似物，目的是使其更容易降解。传统的溶液相合成也将用于合成特别保护的氨基酸，以及克服可能出现的意想不到的障碍。一旦合成，新的类似物将通过高效液相色谱法进行纯化，并测试它们对细菌酶的影响。这些类似物是基于设计指导的方法提出的，希望能够实现对各种细菌酶的抑制，从而使这些肽可以被认为是有希望的抗生素候选者，可能是物种特有的。本研究的目的是帮助了解抗菌肽在生物化学领域的知识，同时与EPSRC的目标保持一致，为创新研究做出贡献。通过结合化学研究和应用生物技术的技术，我们希望增加科学界的知识，这样可能有助于解决日益增长的抗菌素耐药性问题。感染。迪什。2013、56、1685-1694。(2)NAT。“毒品问题国际会议评论”。2002、1(11)、895-910(3)NAT。地中海医院。1998年，4545-546。(注4)J.O‘Neill，《抗菌素耐药性报告》，2014年。(5)世界卫生组织。2017年，(世卫组织/环境保护局/IAU/2017.12)(6)J.NAT。戳。2017、80、1264-1274。(7)生物化学。药水。2017年，133，4-19。(8)NAT。戳。代表2019，36,573-592。(9)J.Mol.比奥尔。2009、385、1422-1432。

The ever increasing threat caused by antimicrobial resistance (AMR) to the quality of healthcare and indeed life, is well documented1-3; it is predicted that by 2050, 10 million people will die annually due to AMR.4 The issue is heightened by a lack of development of new antimicrobial compounds, as well as their overuse in global healthcare.2 Between 2000 and 2010 the medicinal use of antibiotics rose by nearly 40 %.4 Couple this to the antibiotic discovery void of the past few decades, perpetuated by big pharma reducing or removing their antimicrobial Research and Development1, then you get a sense of the scale of the issue. Clearly, this is not an issue that can be ignored now and addressed later; 50 000 are known to die each year across the USA and Europe due to treatable bacterial infections.4 Statistics also tell us 1.8 million people die annually due to Tuberculosis (TB) infections5, which indeed are curable.The need for research and development of new antimicrobial compounds (AMCs) is clear. Fortunately, there remains many untouched avenues in the research field for such medicinal compounds. Peptides provide a promising source of AMCs; they offer diverse structural capacity such that they can kill bacteria via several different avenues, and one can fine tune the properties at the same time as making them more cost-effective. Some well-known antibiotics belong to the polypeptide family, such as Polymyxin B6 and Vancomycin7. Unfortunately, resistance against these antibiotics is already known8,9, further highlighting the need for more research into peptides as antibiotic candidates.Bacteria can be killed in a variety of ways by antibiotics, but perhaps the most effective strategy is to target enzymes involved in essential bacterial processes. The chance of resistance arising is less likely, as the bacteria with refrain from altering processing that will hinder their own survival. Peptides are known to bind to a range of enzymes involved in DNA processes8, as well as hindering other enzymes important for survival.Peptide synthesis is carried out on a solid support, known as Solid Phase Peptide Synthesis (SPPS) and is a relatively straight forward and efficient process. Throughout this research, SPPS will be used to synthesise novel analogues of an antimicrobial peptide, with the aim of making it more stable to degradation. Conventional solution-phase synthesis will also be used to synthesise specifically protected amino acids, as well as to overcome the unexpected obstacles that can arise. Once synthesized, the new analogues will be purified by High Performance Liquid Chromatography and tested for their effects on bacterial enzymes. These analogues have been proposed based on a design guided approach and it is hoped that inhibition of a variety of bacterial enzymes can be achieved such that these peptides can be considered promising antibiotic candidates, which could potentially be species-specific.This research is aimed to aid the knowledge of antimicrobial peptides in the field of Biological Chemistry, while aligning itself with the EPSRC's objective to contribute towards innovative research. By combining skills from both chemical research and applying biological techniques, we hope to add to the knowledge of the scientific community, such that it may be help tackle the growing problem of antimicrobial resistance.(1) Clin. Infect. Dis. 2013, 56, 1685-1694. (2) Nat. Rev. Drug Discov. 2002, 1 (11), 895-910. (3) Nat. Med. 1998, 4, 545-546. (4) J. O'Neill, Antimicrobial Resistance Report, 2014. (5) World Health Organization. 2017, (WHO/EMP/IAU/2017.12) (6) J. Nat. Prod. 2017, 80, 1264-1274.(7) Biochem. Pharmacol. 2017, 133, 4-19. (8) Nat. Prod. Rep. 2019, 36, 573-592. (9) J. Mol. Biol. 2009, 385, 1422-1432.