本文選題：H1N1神經(jīng)氨酸酶 + 突變��； 參考：《鄭州大學(xué)》2011年碩士論文

【摘要】：從2009年四月份以來,H1N1流感病毒的爆發(fā)引起了全世界的關(guān)注。世界衛(wèi)生組織和疾病預(yù)防與控制中心一致認(rèn)為奧司他韋是治療感染流感病毒病人最有效的抗病毒藥物。但是,在2010年二月份世界衛(wèi)生組織宣布已經(jīng)發(fā)現(xiàn)200多個病例出現(xiàn)了針對奧司他韋出抗藥性。 奧司他韋(達(dá)菲)是神經(jīng)氨酸酶(NA)的抑制劑,神經(jīng)氨酸酶在流感病毒復(fù)制,釋放和致病過程中起著非常重要的作用。奧司他韋口服后經(jīng)肝臟和腸道酯酶催化迅速轉(zhuǎn)化為其活性代謝物奧司他韋羧酸,奧司他韋羧酸的構(gòu)型與神經(jīng)氨酸的過渡態(tài)相似,能夠競爭性地與流感病毒神經(jīng)氨酸酶的活性位點結(jié)合。流感病毒NA有9個亞型,根據(jù)遺傳和結(jié)構(gòu)特性分了兩類,第一類NA包括N1,N4,N5,N8,;另一類包括N2, N3, N6, N7和N9。第一類和第二類的不同在于150-loop(殘基147-152)活性位點附近是否有一個大的空腔。但是,催化位點在所有類中都是保守的。催化位點(R118、D151、D152、R224、E276, R292、R371和Y406)被發(fā)現(xiàn)和唾液酸相互作用,而一些輔助位點(E119、R156、W178、S179、D198、1222、E227、H274、E277、N294和E425)被認(rèn)為支持催化位點的結(jié)構(gòu)。在流感病毒NA的N1亞型中,已證實H274Y和N294S流感病毒株對達(dá)菲表現(xiàn)出了強烈的抗藥性。在N2和N9亞型中,感染E119V、I222V和R292K突變株的病人對達(dá)菲表現(xiàn)出了抗性。在2009年爆發(fā)的H1N1流感病毒株中,H274Y突變株對達(dá)菲的敏感性平均降低了1466倍。所以,流感病毒NA活性位點的突變有可能影響到流感病毒株對達(dá)菲的敏感性的改變。 本論文,我們從NCBI數(shù)據(jù)庫中發(fā)現(xiàn)了6種新的H1N1流感病毒NA活性位點改變的突變株(E119K、D151G、S179P、D198G、R292W和Y406H),通過同源建模、分子對接、分子動力學(xué)模擬和自由能計算研究了這些突變株對達(dá)菲的抗藥性,并且對有抗藥性的突變株進(jìn)行了殘基能量分解計算,分析了抗藥性機制。和WT-OTV復(fù)合物比較,突變S179P-OTV和R292W-OTV分別使結(jié)合自由能下降了-9.5 kcal/mol和-11.88 kcal/mol,這表明了S179P和R292W突變對達(dá)菲產(chǎn)生了抗藥性。在突變S179P中,非極性氨基酸脯氨酸取代了極性氨基酸絲氨酸,所以原來起主導(dǎo)作用的極性相互作用降低了2.28kcal/mol。另外Glu227形成的氫鍵數(shù)目的減少也驅(qū)使S179P對達(dá)菲產(chǎn)生抗藥性。在R292W突變中,色氨酸取代精氨酸縮小了側(cè)鏈的大小,這有可能增大了結(jié)合腔的空間,降低了抑制劑與蛋白酶間的親和能。
[Abstract]:The outbreak of the H1N1 influenza virus since April 2009 has attracted worldwide attention. The World Health Organization and the Centers for Disease Control and Prevention agree that oseltamivir is the most effective antiviral drug for influenza patients. However, in February 2010, the World Health Organization announced that more than 200 cases had been found to be resistant to oseltamivir. Oseltamivir (Tamiflu) is an inhibitor of neuraminidase (na), which plays an important role in influenza virus replication, release and pathogenesis. After oral administration, oseltamivir was rapidly transformed into oseltamivir carboxylic acid, a metabolite of oseltamivir carboxylic acid, which was catalyzed by esterase from liver and intestine. The configuration of oseltamivir carboxylic acid was similar to that of neuraminic acid. To be able to competitively bind to the active sites of influenza virus neuraminidase. There are nine subtypes of influenza virus na, which can be classified into two groups according to their genetic and structural characteristics. The first type of na includes N1N4N5N8, and the other includes N2, N3, N6, N7 and N9. The difference between the first and the second is whether there is a large cavity near the active site of 150-loop (residue 147-152). However, the catalytic sites are conserved in all classes. The catalytic sites (R118D151D152H276, R292OR371 and Y406) were found to interact with sialic acid, while some of the auxiliary sites (E119ON156W178S179C D198 1222E227H274E277N294 and E425) were considered to support the structure of the catalytic sites. In the N1 subtype of influenza virus na, H274Y and N294S influenza strains showed strong resistance to Tamiflu. In N2 and N9 subtypes, patients infected with E119VFV I222V and R292K mutants showed resistance to Tamiflu. The sensitivity of the H 274Y mutant to Tamiflu decreased by an average of 1466 times in the 2009 H1N1 influenza virus strain. Therefore, the mutation of na activity site of influenza virus may affect the sensitivity of influenza virus strain to Tamiflu. In this paper, we have found six new H1N1 influenza virus mutants with altered na activity sites (E119KTX D151GN S179PU D198GFR292W and Y406H) from the NCBI database, and linked to each other by homologous modeling and molecular docking. Molecular dynamics simulation and free energy calculation were used to study the resistance of these mutants to Tamiflu, and the residue energy decomposition of resistant mutants was carried out, and the mechanism of drug resistance was analyzed. Compared with WT-OTV complex, mutation S179P-OTV and R292W-OTV reduced binding free energy by -9.5 kcal/mol and -11.88 kcal / mol, respectively, which indicated that S179P and R292W mutations were resistant to Tamiflu. In the mutant S179P, the non-polar amino acid proline replaced the polar amino acid serine, so the dominant polar interaction decreased by 2.28 kcal / mol. In addition, the decrease in the number of hydrogen bonds formed by Glu227 also drives S 179P to develop resistance to Tamiflu. In R292W mutation, tryptophan replaces arginine reduces the size of side chain, which may increase the space of binding cavity and decrease the affinity between inhibitor and protease.
【學(xué)位授予單位】：鄭州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2011
【分類號】：R373

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 ;Highlight the significance of genetic evolution of H5N1 avian flu[J];Chinese Medical Journal;2006年17期

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本文編號：2070723