【摘要】：Sirtuins在許多生物過程以及老齡化疾病中起重要作用,它們除了可以催化去乙�；磻�,還可以催化例如去琥珀�；�、去長鏈脂肪酸酰化等反應。在第一部分工作中,為了研究sirtuins去長鏈脂肪酸酰化的分子機制,我們解析了SIRT3蛋白與肉豆蔻�；⒆貦磅；腍3K9多肽的復合物晶體結(jié)構(gòu),我們發(fā)現(xiàn):肉豆蔻酰、棕櫚�；鶊F結(jié)合在SIRT3蛋白C口袋內(nèi)的不同位置;隨著底物的不同,C口袋也隨之發(fā)生改變。Sirtuin蛋白C口袋的可塑性可以幫助我們設(shè)計sirtuins的抑制劑,也有助于闡釋sirtuins去長鏈脂肪酸的分子機制。Sirtuins抑制劑可作為分子探針用來研究sirtuins的生物功能,并且可作為潛在的老齡化疾病的治療藥物。到目前為止,許多抑制劑結(jié)合在sirtuins的A、B、C口袋。為設(shè)計SIRT5抑制劑,在第二部分工作中,我們解析了SIRT5蛋白與帶香豆素標記的琥珀�；孜锒嚯腶c-LGKsuc-AMC的復合物晶體結(jié)構(gòu)。通過比較“SIRT5/ac-LGKsuc-AMC”、“SIRT5/H3K9suc”(SIRT5與不帶香豆素標記的琥珀酰化H3K9多肽)復合物結(jié)構(gòu),我們發(fā)現(xiàn),由于香豆素所形成的空間位阻,SIRT5蛋白的250-257位氨基酸發(fā)生了較大的構(gòu)象變化。Ser251、Ser252、Val253會向Rossmann折疊移動,因此熒光團分子香豆素(AMC)擴大了蛋白催化區(qū)域的狹縫,該結(jié)構(gòu)可幫助我們設(shè)計小分子化合物來調(diào)節(jié)SIRT5的功能。另外,我們發(fā)現(xiàn)白藜蘆醇的衍生物白皮杉醇是SIRT5蛋白的抑制劑。基于蛋白熱穩(wěn)定性實驗和圓二色譜實驗結(jié)果,我們提出白皮杉醇抑制SIRT5去琥珀�；囊环N機制,即白皮杉醇結(jié)合SIRT5、使得SIRT5處于一種相對穩(wěn)定的構(gòu)象,而SIRT5在催化反應過程中要經(jīng)歷一系列構(gòu)象變化,這種穩(wěn)定的構(gòu)象不利于SIRT5的催化反應。我們還需進一步研究白皮杉醇與SIRT5的具體結(jié)合模式,來確定白皮杉醇抑制SIRT5酶活的作用機理。
[Abstract]:Sirtuins play an important role in many biological processes, as well as in the aging of the disease, which, in addition to the catalytic deacetylation reaction, can also catalyze the reaction of, for example, desulphation, long-chain fatty acid precipitation, and the like. In the first part, in order to study the molecular mechanism of sirtuins to long-chain fatty acid precipitation, we analyzed the crystal structure of the complex of the SIRT3 protein and the deregulated, palm-encapsulated H3K9 polypeptide. We found that: Carnauba-based groups bind to different positions in the pocket of the SIRT3 protein C; as the substrate is different, the C-pocket also changes. The plasticity of the Siruin protein C pocket can help us to design inhibitors of sirtuins and help to explain the molecular mechanism of sirtuins to long-chain fatty acids. the sirtuins inhibitor can be used as a molecular probe to study the biological function of sirtuins and can be used as a therapeutic agent for potential aging diseases. So far, many inhibitors bind to the A, B, and C pockets of sirtuins. To design the SIRT5 inhibitor, in the second part, we resolved the complex crystal structure of the SIRT5 protein and the coumarin-labeled amber-encapsulated substrate polypeptide ac-LGKsuc-AMC. By comparing the structure of the 鈥淪IRT5/ ac-LGKsuc-AMC鈥，

本文編號：2316815