Alliance Protein Laboratories, a Division of KBI Biopharma, 6042 Corner Stone Court West, San Diego, CA 92121, United States of America.
Alliance Protein Laboratories, a Division of KBI Biopharma, 6042 Corner Stone Court West, San Diego, CA 92121, United States of America.
Int J Biol Macromol. 2019 Jul 1;132:1290-1295. doi: 10.1016/j.ijbiomac.2019.04.013. Epub 2019 Apr 3.
Circular dichroism (CD) is widely used for protein structure and interaction analyses. Here, we have studied the structure of four proteins at widely different concentrations ranging from 250 to 0.001 mg/ml using CD. These four proteins showed different concentration dependences of secondary and tertiary structures. Bovine gamma globulin showed near UV CD too weak to detect concentration dependence, while showing no concentration dependence of secondary structure. Lysozyme showed concentration and time dependent changes in secondary structure below 0.002 mg/ml, while showing no dependence of tertiary structure above 0.02 mg/ml. Chymotrypsin showed small, but significant, changes in both secondary and tertiary structures. Bovine serum albumin showed changes in secondary structure at pH 3.0 at low protein concentrations. In conclusion, we demonstrate feasibility of CD analysis to study protein structure at widely different protein concentrations.
圆二色性（CD）广泛用于蛋白质结构和相互作用分析。在这里，我们使用 CD 研究了四种在从 250 到 0.001mg/ml 的广泛浓度范围内的蛋白质的结构。这四种蛋白质表现出不同的二级和三级结构的浓度依赖性。牛γ球蛋白的近紫外 CD 太弱而无法检测到浓度依赖性，而二级结构没有浓度依赖性。溶菌酶在 0.002mg/ml 以下表现出浓度和时间依赖的二级结构变化，而在 0.02mg/ml 以上则没有三级结构依赖性。糜蛋白酶显示二级和三级结构都有微小但显著的变化。牛血清白蛋白在低蛋白浓度下在 pH 3.0 时表现出二级结构的变化。总之，我们证明了 CD 分析在广泛不同的蛋白质浓度下研究蛋白质结构的可行性。
