本文選題：烯烴復分解反應(RCM) + staple��； 參考：《華僑大學》2017年碩士論文

【摘要】：多肽的生物活性與構型密切相關,在多數(shù)情況下,由于靈活多變的結構使得它容易受蛋白酶水解作用的影響以及帶來低效的細胞穿透性;所以穩(wěn)定的多肽構象對于多肽藥物的發(fā)展有重要意義。固定構型后的多肽穿膜機制雖然還未揭示,但通過報道的200多個裝訂肽的攝取方式的統(tǒng)計顯示,影響多肽領域最有價值的性質—細胞穿透性能的因素主要是肽的電荷以及裝訂的位置與類型。在許多情況下,裝訂肽的穿膜性超過未修飾的多肽。目前已經(jīng)出現(xiàn)了很多修飾多肽的方法來使得螺旋構象穩(wěn)定。螺旋穩(wěn)定化的策略包括鹽橋、金屬螯合物和共價環(huán)化方法,例如二硫化物和內酰胺橋。由于連接位置i,i+4,i+7和i+11處于α-螺旋的同一側(i代表肽鏈上某氨基酸所在位數(shù)),所以這些側鏈的共價連接可以促進體系的螺旋構象。Grubbs和Blackwell通過與O-烯丙基絲氨酸殘基的閉環(huán)復分解反應(RCM)開創(chuàng)了非天然碳—碳鍵成環(huán)。該反應在Verdine及其同事發(fā)展下,將非天然α,α-二取代氨基酸與烯烴系鏈引入肽序列中,這種新的碳氫化合物骨架穩(wěn)定方法顯示出最好的穩(wěn)定性與穿膜性能,為后期研究提供了理論依據(jù)。結合近期我們課題組研究發(fā)現(xiàn),在多肽側鏈特定位置引入一個R構型的手性中心,該手性中心有助于多肽形成α-螺旋結構。引入手性中心通過RCM關環(huán)構建環(huán)肽以及RCM關環(huán)本身均會出現(xiàn)異構體問題,出現(xiàn)每種異構體對螺旋度是否具有一致性的問題,擺在了我們面前。這促使我們應用RCM修飾多肽的方法研究其所形成的構型對多肽二級結構的影響,并尋找最優(yōu)構型。基于實驗室前期工作,這次我們研究的重點放在是手性中心對結構的影響。建立短肽模型(X_1-AAA-X_2)來驗證側鏈手性中心對Stapled Peptides的二級構象影響。選取HIV(FITC-Beta-Ala-ITF-X_1-DLL-X_2-YYGP-NH_2)多肽作為靶點,驗證體系通過RCM方法添加手性中心之后該體系穿膜性的變化。(X_1,X_2為S_5、mS_5、mS_5(2-Ph)的一種;mS_5(2-Ph)代表手性中心為S構型,其側鏈為5個碳鍵長度的的非天然氨基酸,且其α位無支鏈(m),在側鏈2位是苯基)。通過結構鑒定、穿膜性能鑒定以及多肽穩(wěn)定性實驗我們得出了Z/R-裝訂肽具有最好α螺旋含量,并且還具有最佳的穿透細胞膜能力及最佳的抗水解能力。
[Abstract]:The bioactivity of polypeptide is closely related to its configuration. In most cases, it is easy to be affected by protease hydrolysis and bring low cell penetration due to its flexible and changeable structure. Therefore, stable polypeptide conformation is of great significance for the development of polypeptide drugs. Although the mechanism of polypeptide transmembrane after fixed configuration has not been revealed yet, the statistics of the uptake patterns of more than 200 binding peptides reported, The most valuable properties in the field of peptides-cell penetration are mainly the charge of peptides, binding position and type. In many cases, binding peptides are more permeable than unmodified peptides. There have been many methods of modifying peptides to stabilize the helix conformation. Spiral stabilization strategies include salt bridges, metal chelates, and covalent cyclization methods, such as disulfide and lactam bridges. Because the junction positions iGrubbs and i11 are located on the same side of the 偽 -helix to represent the number of amino acids on the peptide chain, the covalent bonding of these side chains can promote the helical conformation of the system. Grubbs and Blackwell promote the helical conformation of the system by interacting with O- allyl sericin. The closed-loop double decomposition reaction of acid residues (RCM) creates unnatural carbon-carbon bond ring formation. With the development of Verdine and his colleagues, the unnatural 偽, 偽 -disubstituted amino acids and alkenes were introduced into the peptide sequence. It provides a theoretical basis for the later study. In combination with our recent research, we found that a chiral center of R configuration was introduced at the specific position of the peptide side chain, which was helpful to the formation of 偽 -helix structure of the peptide. The introduction of chiral centers to construct cyclic peptides via RCM ring and the problem of isomers appearing in RCM ring itself, and the question of whether each isomer has consistency on helicity is in front of us. This prompted us to use RCM modified polypeptide method to study the influence of its configuration on the secondary structure of polypeptide and to find the optimal configuration. Based on prelab work, our focus this time is on the effects of chiral centers on structures. Short peptide model X _ 1-AAA-X _ 2) was established to test the effect of chiral center of side chain on the secondary conformation of Stapled peptides. Using the HIVFITC-Beta-Ala-ITF-X1-DLL-X2-YYGP-NH2) peptide as the target, the verification system verifies the change of the system's membrane penetration after the chiral center is added by the RCM method. Moreover, the 偽 -site has no branched chain, and the second position in the side chain is phenyl. Through the structure identification, membrane performance identification and polypeptide stability test, we obtained that the Z / R binding peptide has the best 偽 helix content, and also has the best ability to penetrate the cell membrane and the best ability to resist hydrolysis.
【學位授予單位】：華僑大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O629.72

【參考文獻】

相關期刊論文 前1條

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本文編號：2009631