XeCl准分子激光辐照能量变化对溶菌酶结构与活力的影响  

Effect of Different Energy XeCl Laser Radiation on Lysozyme Structure

作　　者：倪志华[1,2] 张玉明[1] 赵晓辉[3,4] 陈景春[3,4] 王淑芳[3,4] 

机构地区：[1]河北大学生命科学学院 [2]河北省生物工程技术研究中心 [3]新能源光电器件国家地方联合工程实验室 [4]河北大学物理科学与技术学院,保定071002

出　　处：《科学技术与工程》2014年第26期26-31,共6页Science Technology and Engineering

基　　金："973"计划项目(2007CB935700);河北省教育厅计划(z2012206);保定市科技局计划(12ZN012)资助

摘　　要：采用XeCl准分子激光器,以不同能量密度激光(0.1 mJ/mm2,0.3 mJ/mm2,0.5 mJ/mm2)辐照溶菌酶,研究辐照后酶活力和蛋白质结构变化。以SDS-PAGE方法检测酶分子间聚合情况,并结合荧光光谱、圆二色光谱变化,探讨不同能量密度激光辐照对溶菌酶活力和分子结构变化规律。结果表明,较低能量密度(0.1 mJ/mm2,0.3 mJ/mm2)辐照,溶菌酶的荧光光强和酶活力随着辐照剂量(脉冲数)的增加出现先上升后下降的规律变化,而较高能量激光辐照(0.5 mJ/mm2)导致溶菌酶活力和荧光光强均呈下降趋势,这说明激光辐照导致的溶菌酶活力和分子结构变化存在剂量依赖效应。SDS-PAGE显示,随着辐照能量密度和脉冲数的增加,溶菌酶出现了更多的分子间聚合。较低能量密度辐照时,聚合是由分子间二硫键形成的,而较高能量密度诱发的分子聚合是由分子间二硫键及疏水键协同作用形成的。圆二色光谱分析显示,激光辐照使溶菌酶分子内α螺旋和转角的含量均呈现不同程度下降,β-折叠和无序的氨基酸无规则卷曲的比例均有升高,这说明溶菌酶活力的降低及分子聚合是由溶菌酶分子二级结构改变造成的。To study the radiation effect of laser energy on conformation and bio-activity of lysozyme, XeCI exci-mer laser was conducted using at varied energy density （0. 1 mJ/mm2 ,0. 3 mJ/mm2 ,0. 5 mJ/mm2）. Aggregationbetween lysozyme molecules was analyzed by SDS-PAGE, fluorescence spectroscopy and circular dichroism spec-troscopy. And the relation between the features of lysozyme （bio-activity and molecular structure） and irradiationwas extensively studied at different energy density of laser. When low energy density of laser （0. 1 mJ/mm2, 0.3mJ/mm2） was studied, fluorescence intensity and bio-activity of lysozyme were improved at the first stage. Howev-er, the opposite results were observed when further irradiation was conducted. When high energy density of laser（0.5 mJ/mm2 ） was evaluated, fluorescence intensity and bio-activity of lysozyme were always show downwardtrends. The results of SDS-PAGE showed that aggregation between molecules of lysozyme occurred after radiation.Aggregation induced by at low energy density of laser radiation was caused by disulfide bond linkage between molec-ular, and aggregation induced by at high energy density of laser radiation was deduced to be the results of synergis-tic effect between disulfide bond and hydrophobic bond. Results of circular dichroism spectroscopy showed, afterlaser radiation, the ratio of a-helix and 13-turn decreased in lysozyme molecule. Meanwhile, the ratio of B-sheetand random peptide chain increased at the same time. So, we can deduce that the lower bio-activity and moleculeaggregation of lysozyme was induced by the change of protein secondary structure.

关 键 词：激光辐照 能量密度 溶菌酶 荧光光谱 活性 SDS-PAGE 圆二色谱 

分 类 号：Q631[生物学—生物物理学]