本文選題：Mn-oxo咔咯 + DNA��； 參考：《華南理工大學(xué)》2016年碩士論文

【摘要】：咔咯是和卟啉結(jié)構(gòu)類似的18π電子結(jié)構(gòu)的大環(huán)分子,近年來逐漸引起人們的廣泛關(guān)注。研究表明過渡金屬咔咯配合物同樣具有催化氧化斷裂DNA的反應(yīng)活性,并且可能是由于產(chǎn)生活性金屬-oxo物種引起的。目前,過渡金屬咔咯配合物與DNA的相互作用的理論研究還不多見,相關(guān)相互作用以及斷裂機(jī)理有待深入研究。本文采用量子力學(xué)和分子對(duì)咔咯金屬-oxo與DNA的相互作用進(jìn)行了理論研究,主要內(nèi)容如下:1.采用DFT方法對(duì)不同自旋態(tài)的Mn-oxo咔咯配合物以及其氧化反應(yīng)中間體和產(chǎn)物分別進(jìn)行結(jié)構(gòu)優(yōu)化,并對(duì)配合物的前線軌道和自旋密度進(jìn)行分析。結(jié)果表明,基態(tài)和三線態(tài)的Mn-oxo咔咯配合物中的Mn≡O(shè)結(jié)構(gòu)具有氧化活性,能使堿基失去電子并發(fā)生電荷轉(zhuǎn)移氧化斷裂DNA的初始反應(yīng);而五重態(tài)的Mn-oxo咔咯配合物中Mn≡O(shè)結(jié)構(gòu)的O原子表現(xiàn)出自由基性質(zhì),從而能攝取核糖上的H原子并發(fā)生氧轉(zhuǎn)移氧化斷裂DNA的初始反應(yīng)。2.采用分子對(duì)接方法研究三個(gè)帶有不同取代基的Mn-oxo咔咯配合物分別和AT、GC堿基對(duì)序列DNA的相互作用和結(jié)合構(gòu)象的結(jié)構(gòu)特征。結(jié)果表明,不同取代基的Mn-oxo咔咯配合物和AT堿基對(duì)序列DNA只存在小溝結(jié)合模式,而和GC堿基對(duì)序列DNA則存在大溝結(jié)合和小溝結(jié)合這兩種結(jié)合模式。同時(shí),因?yàn)椴煌〈约叭〈鶎?duì)咔咯環(huán)電荷的影響使Mn-oxo咔咯配合物在小溝的結(jié)合構(gòu)象也存在明顯的區(qū)別,而這直接影響了結(jié)合構(gòu)象中涉及氧轉(zhuǎn)移氧化斷裂DNA反應(yīng)的O-H距離長(zhǎng)度。3.采用分子動(dòng)力學(xué)方法模擬對(duì)接結(jié)果中的最優(yōu)結(jié)合構(gòu)象,分析結(jié)合構(gòu)象的運(yùn)行軌跡和Mn-oxo咔咯和DNA的相互作用能隨時(shí)間的變化。結(jié)果表明,Mn-oxo咔咯配合物在AT堿基對(duì)序列DNA小溝的結(jié)合相比GC堿基對(duì)序列DNA小溝更穩(wěn)定,而且和AT堿基對(duì)序列結(jié)合的構(gòu)象中的H-O距離長(zhǎng)度也要更短且其變化也更加穩(wěn)定。而在GC堿基對(duì)序列DNA大溝結(jié)合時(shí),配合物的構(gòu)象發(fā)生了較大的變化但一直保持結(jié)合在大溝位點(diǎn)。
[Abstract]:Caco is a macrocyclic molecule with 18 蟺 electronic structure similar to porphyrin structure, which has attracted more and more attention in recent years. The results show that the transition metal carbolic complexes have the same catalytic activity for the oxidation of DNA and may be due to the production of active metal-oxo species. At present, there are few theoretical studies on the interaction between transition metal and DNA, and the related interaction and fracture mechanism need to be further studied. In this paper, quantum mechanics and molecular analysis are used to study the interaction between DNA and the metal-oxo. The main contents are as follows: 1. DFT method was used to optimize the structure of Mn-oxo complexes with different spin states, as well as the intermediates and products of their oxidation reactions. The frontier orbitals and spin densities of the complexes were also analyzed. The results show that the mn 鈮，

本文編號(hào)：1815631