过氧化物模拟酶的结构设计及初步作用机制研究

发布时间：2018-04-22 17:31

本文选题：过氧化氢模拟酶 + 卟啉环　；参考：《吉林大学》2012年硕士论文

【摘要】：以铁卟啉为辅基的天然过氧化物酶由于轴向配体受蛋白质骨架影响因此配位能力有很大的提高。组氨酸残基通过轴向配位的方式与卟啉中心上的铁原子进行配位，因此可以促进中间体Fe(v)=O活性。本实验室前期根据以血红素为辅基的过氧化物酶的结构，设计合成一个具有过氧化物酶活性的次血红素六肽（Deuterohemin-AlaHisThrValGluLys，DhHP-6）。为了进一步研究组氨酸在过氧化物模拟酶活性中心的作用，本文以丙氨酸替换组氨酸设计DhAP-6（Deuterohemin-AlaAlaThrValGluLys）及去铁的PHP-6（DP-AlaHisThrValGluLys）。本论文研究了DhHP-6、DhAP-6及PHP-6体外酶催化作用机制。并进一步以秀丽线虫为模型，研究了DhHP-6、DhAP-6及PHP-6体内生物学活性。通过给药前后野生型秀丽线虫寿命的影响、TJ356（daf-16::GFP）突变体线虫DAF-16入核以及野生型线虫体内自由基及超氧化物歧化酶变化，来研究DhHP-6作为一种过氧化物模拟酶结构机制，，DhHP-6能延长野生秀丽线虫寿命，促进TJ356（daf-16::GFP）突变体线虫DAF-16入核，清除野生型秀丽线虫体内的自由基及提高超氧化物歧化酶活性。根据DhHP-6、DhAP-6及PHP-6体外酶学及光谱学结构表征及体内活性数据，DhHP-6分子中的组氨酸残基的侧链咪唑基团和卟啉环中心铁原子的配位对其过氧物酶活性起到了关键作用。
[Abstract]:The coordination ability of the natural peroxidase with iron porphyrin as the cogroup was greatly improved because the axial ligand was affected by the protein skeleton. Histidine residues are coordinated with iron atoms in porphyrin centers by axial coordination, thus promoting the Fe(v)=O activity of the intermediate. According to the structure of peroxidase with heme as the cogroup, a peroxidase activity of Deuterohemin-AlaHisThrValGluLyslysDhHP-6 was designed and synthesized in our laboratory. In order to further study the role of ammonia acid in the activity center of peroxidase mimics, the design of DhAP-6 Deuterohemin-AlaAla-AlaAlaAlaGluLysysysys) and the deferrifying PHP-6 DP-AlaHisThrValGluLyslyslys1) were designed with alanine instead of histidine. In this paper, the catalytic mechanism of DhHP-6 DhAP-6 and PHP-6 in vitro was studied. Furthermore, the biological activities of DhHP-6 and PHP-6 in vivo were studied based on the model of DhHP-6 and DhAP-6. The changes of free radicals and superoxide dismutase (SOD) in wild nematode were studied by the effect of DAF-16 on the life span of wild nematode before and after administration of TJ356daf-16: GFP, and the changes of free radicals and superoxide dismutase (SOD) in wild nematode. To study the mechanism of DhHP-6 as a peroxide-mimic enzyme, DhHP-6 can prolong the life span of wild nematode, promote the entry of DAF-16 into the nucleus of TJ356daf-16: GFP-mutant, scavenge free radicals and improve the activity of superoxide dismutase (SOD) in wild nematode. According to the in vitro enzymatic and spectral structure of DhHP-6 and PHP-6, and the in vivo activity data, the side chain imidazole group of histidine residue and the coordination of iron atom in porphyrin ring play a key role in the peroxidism enzyme activity of DhHP-6 molecule.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R341

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