Establishing an Approach for the Selection and Design of Secondary Structure Mimetics to Antagonise Protein-protein Interactions.

蛋白质之间的相互作用是大多数生物过程的中介，因此是重要的治疗靶点。蛋白质的生物活性通常只源于其表面的一小块局部区域。在分子水平上，这些区域通常对应于蛋白质中的关键二级结构，即α-螺旋或β-折叠。创造能够模仿这些区域的分子，同时保持它们的结构，是药物设计的诱人选择。然而，在缺少蛋白质其余部分的情况下，蛋白质的短区域通常不能采用这些结构。相反，除了它们不能穿过生物膜和生物利用度差等其他缺点外，它们还形成了容易降解的随机结构。为了绕过这些问题，我们将与二级结构模拟的世界领先者Fairlie合作，创造能够分离形成具有生物活性的α-螺旋和β-折叠的多肽。这将通过将螺旋或链诱导的系链引入我们日益增长的文库衍生多肽集合中来实现。较短的限制性多肽可以从已知与其靶标高亲和力结合的较大的多肽中衍生出来。我们的努力将集中在我们有记录的两个关键领域：i)创造多肽来对抗致癌转录调节因子激活蛋白-1。我们以前曾使用文库筛选试验来衍生出一系列能够拮抗功能的多肽。我们已经与Fairlie合作，通过瞄准一个被称为CFO的AP-1合作伙伴并在这个过程中去除超过40%的多肽来证明这种方法的可行性。使用这种方法，我们能够获得稳定的针对其目标蛋白的螺旋限制性多肽，这些多肽也能抵抗降解(Rao等人，PLOS One 2013)。我们认为，通过靶向另一个AP-1组分cJun可以实现更高亲和力的相互作用，在那里可以形成高结合亲和力所需的更多疏水相互作用。以前的相关工作已经证明，这种方法可以产生短于5个氨基酸的系链多肽(Harison等人，PNAS，2010)，能够满足药物所需的许多要求，如高稳定性和对生物分解的抗性。Ii)产生能够调节淀粉样蛋白形成的多肽。我们已经使用文库筛选来获得与阿尔茨海默氏症β-淀粉样肽结合的小β链肽(Acerra等人，Protein Eng des Sel 2013)。我们现在寻求与Fairlie合作，创造这些短肽的模拟物，从而产生能够绕过上述许多问题的改进化合物。为了实现这些目标，梅森将在三年内前往昆兰大学分子生物科学研究所(IMB)进行三次访问，以进一步发展我们与Fairlie小组的合作。费利是国际知名的化学、生物化学、药理学和药物发现领域的研究和意见领袖。该奖项将允许梅森获得新的技能和技术，这些技能和技术可以带回埃塞克斯并在英国进一步发展，此外，还可以交流思想和进一步发展合作。在已经开发出稳定α-螺旋和β-链的方法之后，将有相当大的范围将这些技术以及随后的肽和肽模拟设计规则应用于其他肽系统。最后，在昆士兰期间，还将有大量机会与IMB的其他成员(如Glenn King教授和David Craik教授)举行研讨会，并与他们讨论研究计划，这些成员对开发基于多肽的药物有类似的兴趣。

Protein-protein interactions mediate most biological processes and are therefore important therapeutic targets. The biological activity of a protein usually stems from only a small localised region on its surface. At the molecular level such regions often correspond to key secondary structures known as alpha-helices or beta-sheets that reside within the protein. Creating molecules able to mimic these regions while retaining their structure are attractive options for drug design. However short regions of a protein are usually unable to adopt these structures in the absence of the rest of the protein. Rather, they populate random structures that are susceptible to degradation in addition to other shortcomings such as their inability to cross biological membranes and poor bioavailability. To circumvent these issues we will collaborate with the Fairlie, a world leader in secondary structure mimetics, to create peptides that are able to form bioactive alpha-helices and beta-sheets in isolation. This will be achieved by introducing helix- or strand-inducing tethers into our growing collection of library derived peptides. Shorter constrained peptides can be derived from larger peptides known to bind with high affinity to their target. Our efforts will focus on two key areas in which we have track record:i) creating peptides to antagonise the oncogenic transcriptional regulator, Activator Protein-1. We have previously used library screening assays to derive a range of peptides capable of antagonising function. We have already worked with Fairlie to demonstrate feasibility for this approach by targeting one AP-1 partner known as cFos and shedding over 40% of the peptide in the process. Using this approach we were able to derive stable helix-constrained peptides specific for their target protein that also resisted degradation (Rao et al, PLOS One 2013). We believe that much high affinity interactions can be achieved by targeting another AP-1 component, known as cJun, where many more hydrophobic interactions required for high binding affinity can be formed. Previous related work has demonstrated that this approach can yield tethered peptides as short as five amino acids (Harrison et al, PNAS, 2010) that are able to meet many of the requirements necessary for a drug, such as high stability and resistance to biological breakdown. ii) Creating peptides capable of modulating amyloid formation. We have used library screening to derive small beta-strand peptides that bind to the Alzheimer's beta-amyloid peptide (Acerra et al, Protein Eng Des Sel 2013). We now seek to collaborate with Fairlie in creating mimetics of these short peptides that result in improved compounds that are able to circumvent many of the above issues. To achieve these goals Mason will travel to the Institute for Molecule Bioscience (IMB) at the University of Queenland on three visits over three years to further develop our collaboration with the Fairlie group. Fairlie is internationally known as a research and opinion leader in chemistry, biochemistry, pharmacology, and drug discovery. The award will permit Mason to gain new skills and techniques that can be brought back to Essex and further developed in the UK, in addition to the exchange of ideas and the further development of the collaboration. Having developed methods for stabilising alpha-helices and beta-strands in general there will be considerable scope to apply these techniques, and consequent rules for peptide and peptide mimetic design, to other peptide systems. Finally while at Queensland there will also be ample opportunity to hold seminars and meet and discuss research plans with other members of the IMB (e.g. Professors Glenn King and David Craik) who have similar interests in developing peptide-based drugs.