摘要
运用荧光、圆二色谱及紫外光谱手段,研究了六种不同物理或化学条件处理后,牛乳铁蛋白(Bovine lactoferrin,bLF)三级、二级结构及二硫键的变化。荧光结果显示:6mol.L-1盐酸胍、8mol.L-1尿素和50mmol.L-1二硫苏糖醇三种处理后bLF溶液的最大发射波长从333nm红移至354nm,疏水基团大量暴露,三级结构发生明显变化;100℃加热5min、超声(450W,5s,6个脉冲)、1%巯基乙醇处理后,bLF溶液荧光强度明显减弱,最大发射波长几乎无变化。圆二色谱结果表明:经盐酸胍处理,bLF中α-螺旋结构消失,其余五种处理,二级结构的变化较小。紫外光谱数据表明:二硫苏糖醇对bLF二硫键破坏最严重,超过总二硫键含量的55%,超声次之,盐酸胍、巯基乙醇和加热破坏较少。结果对进一步明确乳铁蛋白的构效关系提供了一定的依据。
In this study,the tertiary,secondary structures and disulfide bond changes o f bovine lactoferrin（bLF） under 6 differents physico-chemical treatments were i nvestigated by fluorescence,circular dichroism（CD） and UV-Vis absorption.A re d shift from 333 to 354 nm in the fluorescence emission maximum（λmax） was observed in the bLF treated by 6 mol·L-1 GdnHCl,8 mol·L-1 Urea and 50 mmol·L-1 DTT simultaneously,meanwhile a large number of exposed hydrophobic groups were detected.However,there was no marked shift in λmax of bLF treated by heating（100 ℃,5 min）,Ultrosonic（450 W,5 s,6 pulses） or β-ME（1%）,of which fluorescence intensity d ecreased significantly compared with the untreated bLF.The results indicated that the mechanism of changes in tertiary structure of the former three methods were different from the latter three.The detection by CD showed that the αhelix structure vanished completely in the bLF treated by GdnHCl.However,th ere was no remarkable change in the secondary structure of the bLF treated by th e other five methods.In addition,UV-Vis absorption suggested that disulfide bond was seriously destructed in the bLF treated by DTT and Ultrosonict,but Gd nHCl,β-ME and heating induced a little damage merely.This study is instruct ive and meaningful to the further research on relationship between structure and activity of bLF.
作者
文鹏程
余丹丹
汪昕昕
张录达
任发政
雷新根
郭慧媛
WEN Peng-cheng;YU Dan-dan;WANG Xin-xin;ZHANG Lu-da;REN Fa-zheng;LEI Xin-gen;GUO Hui-yuan(College of Food Science&Engineering,Gansu Agricultural University,Lanzhou 730070,China;Key Laboratory of Functional Dairy,Ministry of Education,China Agricultural University,Bering 100083,China;Bering Higher Institution Engineering Research Center of Animal Product,Beijing 100083,China;Cornell University,Ithaca,New York,USA)
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2012年第1期162-165,共4页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(31000771)
高等学校博士学科点专项科研基金项目(20100008120009)资助
关键词
牛乳铁蛋白
空间构象
荧光光谱
圆二色光谱
二硫键
Bovine lactoferrin
Circular dichroism
Spectroscopic analysis
Structure charac teristic
Disulfide bond
