NCL with induced a-Helices: de Novo Chemical Synthesis of the ATAD2 bromodomain

描述(由申请人提供)：蛋白质的从头化学合成通过提供快速获得天然和合理设计的非天然蛋白质的途径，有可能迅速加速蛋白质的研究。然而，由于一些实际因素，目前蛋白质的化学合成仅限于相对较小的多肽和糖肽。一般来说，多肽片段的连接效率随着多肽长度的增加而降低，其中多肽聚集是经常观察到的障碍。我们提出了另一种保护多肽免受聚集和天然连接的大小限制的范式，而不是引入额外的保护功能和辅助物质。容易形成α-螺旋的多肽片段在溶液中的二级结构的诱导应通过将多肽骨架刚性化为致密构象来保护多肽免受破坏性聚集。这一推理与典型的天然化学连接协议形成了鲜明对比，传统上，这种连接协议只在变性条件下执行。除了减少聚集的倾向外，我们预计螺旋蛋白片段由于构象紧凑和刚性而具有更高的连接效率，并且多肽复杂性和连接效率之间的负相关性相应地降低。为了研究这种多肽连接的方法，我们将合成人蛋白ATAD2的溴域。仅在过去的几年中，这种蛋白在乳腺、前列腺、肺和卵巢肿瘤中被发现上调，许多研究表明ATAD2的过度表达与肿瘤的生长和患者的预后有关。考虑到ATAD2参与蛋白质转录和有丝分裂，以及在多种肿瘤类型中观察到的上调，ATAD2被确定为一种潜在的治疗方法也就不足为奇了。 目标。ATAD2的溴结构域是检验螺旋稳定假说的理想靶点，因为它由五个α-螺旋组成，每个α-螺旋的大小都适合固相肽合成，并且包括两个相对疏水的区域，具有聚集的潜力。这项研究有可能产生广泛的影响，因为拟议的蛋白质化学合成的战略修订应用了新的规则，将多肽断开为其相应的片段。

DESCRIPTION (provided by applicant): The de novo chemical synthesis of proteins has the potential to rapidly accelerate the study of proteins by providing rapid access to natural and rationally designed unnatural proteins. Currently, however, chemical synthesis of proteins is limited to relatively small sized polypeptides and glycopeptides, due to a number of practical factors. Generally, the efficiency of ligation of peptide fragments decreases with increasing peptide length, where peptide aggregation is an often observed obstacle. We propose an alternative paradigm for the protection of peptides against aggregation and the size limitations of native ligation, in contrast to the introduction of extraneous protection functionalities and auxiliaries. The induction of secondary structure in solution for peptide fragments that are predisposed to the formation of alpha-helices should serve to protect the peptides against destructive aggregation by rigidifying the peptide backbone into a compact conformation. This line of reasoning is in stark contrast to the typical native chemical ligation protocol that is historically performed exclusively under denaturing conditions. In addition to reduced propensity towards aggregation, we expect the helical protein fragments to have increased efficiency of ligation due to the conformation compactness and rigidity, and a corresponding reduction in the negative correlation between peptide complexity and ligation efficiency. In order to investigate this approach towards peptide ligation, the bromodomain of human protein ATAD2 will be synthesized. In only the past few years, this protein has been identified as upregulated in breast, prostate, lung, and ovarian tumors, and numerous studies have correlated the over expression of ATAD2 with cancer growth and patient prognosis. Considering the involvement of ATAD2 with protein transcription and mitosis along with the upregulation observed in a wide variety of tumor types, it is no surprise that ATAD2 has been identified as a potential therapeutic target. The bromodomain of ATAD2 is an ideal target to test the helical stabilization hypothesis because it is made up of five alpha-helices, each of ideal size for solid phase peptide synthesis, and includes two relatively hydrophobic regions with potential for aggregation. This investigation has the potential for broad implications, as the strategic revision for the chemical synthesis of proteins that is proposed applies new rules for the disconnection of polypeptides into their corresponding fragments.