基于共价策略阿兹海默症相关蛋白Aβ抑制剂的合成与评价

发布时间：2018-04-08 23:01

本文选题：阿尔兹海默症　切入点：淀粉样多肽Aβ　出处：《清华大学》2012年硕士论文

【摘要】：阿尔兹海默症是痴呆症中最为普遍的一种，患者会出现认知能力、空间能力、乃至行动能力障碍，并且最终导致死亡。其致病机制受到多方面影响，其中大脑中淀粉样多肽Aβ水平上升及Aβ错误折叠被普遍认为与阿尔兹海默症直接相关。研究表明，Aβ可以错误折叠为富含β折叠结构的纤维状聚集体，这些聚集体具有神经细胞毒性。本研究为了抑制Aβ有毒聚集体的产生，设计合成并且评价了一系列共价多肽抑制剂。基于共价策略的抑制剂在神经退行性疾病的研究中还未被普遍应用，在应用于阿尔兹海默症的各种抑制剂分子、药物分子、检测分子中未见报道。本研究希望将共价策略应用到各种针对阿尔兹海默症的分子中，并对未来的药物研发、疾病检测等做出有益贡献。研究首先进行了Aβ抑制剂的设计与合成。应用共价策略设计的抑制剂多肽分子包含两个部分：识别片段和共价结合片段。因为多肽在识别中具有高度特异性，，所以识别片段选择能与Aβ16-20聚集疏水核心区相互作用的多肽片段。共价基团选择异硫氰基，因其在生理环境下可以高效地与氨基酸上的游离氨基发生反应，生成硫脲键。综合异硫氰基和不同的多肽识别片段的选择，本研究中设计并合成了6个具有共价功能的多肽。通过实验确证了它们具有共价反应活性，并且从中筛选出具有最好的抑制Aβ聚集为β折叠结构聚集体能力的抑制剂：P9-NCS。而后将P9-NCS对Aβ的聚集性质和共价反应位点进行进一步研究。研究结果表明P9-NCS可以特异性的与Aβ共价反应并产生硫脲键，且优势反应位点为Aβ上第16位赖氨酸的侧链氨基。即P9-NCS的识别片段倾向于首先通过非共价相互作用特异性地与Aβ16-20区域结合，将异硫氰基带到此区域附近帮助其与Aβ的Lys16的侧链氨基发生共价反应，由此强化相互作用。此外，P9-NCS可以有效抑制Aβ聚集为富含β折叠结构的纤维丝，并促进Aβ聚集为无定形聚集体。从细胞实验数据可知，P9-NCS可以抑制Aβ聚集产生的细胞毒性。而不含共价基团的对照组多肽就没有上述性质。这类具有特异识别功能的多肽共价分子能够因其位点选择性、稳定的共价作用等特点有望被广泛研究并用于阿尔兹海默症的治疗、检测等方面。
[Abstract]:Alzheimer's disease is the most common in patients with dementia, there will be cognitive ability, spatial ability, and action ability disorder, and eventually death. Its pathogenic mechanism is influenced by many aspects, which increased A beta amyloid peptide levels in the brain and A beta error folding is generally considered directly related to Alzheimer Alzheimer's disease. The study shows that the A beta can misfolding is rich in beta folding structure of fibrous aggregates, these aggregates with nerve cell toxicity. In this study, in order to suppress the A beta toxic aggregates, and evaluate the design and synthesis of a series of covalent peptide inhibitors. In the study of covalent inhibitor strategy in neurodegenerative disease is not is widely used in a variety of drugs based on molecular inhibitors, applied to Alzheimer's disease, has not been reported in molecular detection. This research hopes to use the covalent strategy Some of the molecules aimed at Alzheimer's disease have contributed to future drug development, disease detection, and so on.
Firstly, the design and synthesis of A beta inhibitors. Inhibitor peptide design and application of covalent strategy consists of two parts: identification of fragment binding fragments and covalent. Because polypeptide has high specificity in recognition, so the recognition polypeptide fragment fragment selection with A beta 16-20 hydrophobic aggregation core area interaction. Covalent group selection isothiocyanato, because it can efficiently react with free amino acids in the physiological environment, generate thiourea key. Peptides fragment isothiocyanato comprehensive and different choice, this research design and synthesis of 6 polypeptides with covalent function. Through the experiment confirmed they have covalent reaction activity, and screened out the best inhibitor with inhibition of A beta aggregation p-sheet aggregate capacity: P9-NCS.
And then the P9-NCS of A beta aggregation properties and covalent reaction sites were further studied. The results show that P9-NCS can specifically and A beta covalent reaction and produce thiourea bonds, and the dominant reaction sites for A beta sixteenth lysine side chain amino. The identification of P9-NCS fragments tend to first through non covalent specific interactions with A beta 16-20 binding region, side chain amino isorhodanic near this area to help the baseband and A beta Lys16 covalent reaction, thereby strengthening the interaction. In addition, P9-NCS can effectively inhibit A beta aggregation fiber rich beta folding structure, and promote the accumulation of A beta amorphous aggregates of cells. From the experimental data showed that the cytotoxicity of P9-NCS can inhibit A beta aggregation produced. The control group without covalent groups of polypeptides do not have such properties.
This kind of polypeptide covalent molecules with specific recognition function can be widely studied and applied to the treatment and detection of Alzheimer's disease because of its site selectivity, stable covalent interaction and so on.

【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R749.16;TQ464.7

【共引文献】