细胞色素c与NO相互作用的光谱研究  

Spectral study on the interaction between cytochrome c and NO

作　　者：唐乾[1,3] 李玲兢 李如玉 曹洪玉[1,3] 王立皓 郑学仿[3] TANG Qian;LI Ling-jing;LI Ru-yu;CAO Hong-yu;WANG Li-hao;ZHENG Xu-fang(College of Life Science and Biotechnology,Dalian University,Dalian 116622,China;College of Environmental and Chemical Engineering,Dalian University,Dalian 116622,China;Liaoning Key Laboratory of Bio-organic Chemistry,Dalian University,Dalian 116622,China)

机构地区：[1]大连大学生命科学与技术学院,辽宁大连116622 [2]大连大学环境与化学工程学院,辽宁大连116622 [3]大连大学辽宁省生物有机化学重点实验室,辽宁大连116622

出　　处：《化学研究与应用》2020年第10期1862-1873,共12页Chemical Research and Application

基　　金：国家自然科学基金资助(21571025,21601024,21601025,21601023)。

摘　　要：目的:为了探究NO与细胞色素c(Cyt c)的结合反应过程以及其对血红素蛋白构象的影响。方法:本文采用紫外-可见吸收光谱、荧光光谱、同步荧光光谱、圆二色等光谱法研究不同价态Cyt c、不同影响因素下,Cyt c直接与NO之间的结合反应,并且阐述了NO与Cyt c反应的荧光猝灭机制。结果表明:NO更容易与三价铁Cyt c(Cyt c-Fe(III))反应。NO不仅能与蛋白质氨基酸侧链弱结合,还能与血红素铁发生紧密结合。通过荧光猝灭机制可知:NO与Cyt c结合为静态猝灭,二者以静电引力等弱结合力结合,结合位点数为1。同时,受NO诱导作用,Cyt c中血红素Fe-S键变弱促进NO与Cyt c的紧密结合。二者结合受到NO浓度的影响。溶液中游离芳香族氨基酸均促进两者结合反应,其中Tyr促进作用最强;355 nm激光照射促进NO与Cyt c的结合;但有Phe、Trp残基存在时激光照射却阻碍了结合作用。NO与Cyt c的结合会改变Cyt c蛋白构象及周围氨基酸残基的微环境,导致肽链伸展,极性增强。意义:本文结果对于进一步研究NO气体小分子与血红素蛋白结合以及在不同因素条件下对血红素环境的影响有重要意义。Objective:Our purpose is to investigate the binding reaction of NO with Cytochrome c(Cyt c)and its effect on the conformation of heme protein.Methods:In this paper,the kinetic method was used to study the binding reaction between Cyt c and NO under different valence states Cyt c and different influencing factors,and the fluorescence quenching mechanism of NO and Cyt c reaction was described.The results show that compared with the ferrous-Cyt c(Cyt c-Fe(II)),NO is more likely to react with the ferric-Cyt c(Cyt c-Fe(III)),and the NO derivative pair may be formed in the solution.NO can not only weakly bind with protein amino acid side chains,but also tightly bind with heme iron.The fluorescence quenching mechanism caused by the combination of NO and Cyt c is static quenching,and the two bind by weak binding force such as electrostatic attraction,and the number of binding sites is 1.The heme Fe-S bond in Cyt c weakened to promote the tight binding of NO to Cyt c.The combination of both is affected by the concentration of NO.The free aromatic amino acids in the solution promote the combination reaction,of which Tyr promotes the strongest.Laser irradiation in 355 nm can promote the binding of NO to Cyt c.However,in the presence of Phe and Trp residues,laser irradiation hinders the binding effect.Both are more readily bound in the presence of the anionic surfactant AOT.Binding of NO to Cyt c alters the microenvironment of the Cyt c protein conformation and surrounding amino acid residues,which causes the peptide chain to stretch and the polarity is enhanced.Signification:The results of this paper are great significance for further study on the effect of NO gas small molecule and heme protein binding on heme environment under different factors.

关 键 词：细胞色素C ProliNONOate 不同因素 结合反应 构象变化 

分 类 号：O61[理学—无机化学] O657.3[理学—化学]