Lu Ming-Feng, Ji Hong-Fang, Li Ting-Xuan, Kang Shou-Kai, Zhang Yue-Jie, Zheng Jue-Fei, Tian Tian, Jia Xi-Shuai, Lin Xing-Ming, Zhang Hong-Yu
School of Life Sciences, Shandong Normal University, Jinan 250014, China.
Int J Mol Sci. 2013 Jun 19;14(6):12843-52. doi: 10.3390/ijms140612843.
Primitive proteins are proposed to have utilized organic cofactors more frequently than transition metals in redox reactions. Thus, an experimental validation on whether a protein constituted solely by early amino acids and an organic cofactor can perform electron transfer activity is an urgent challenge. In this paper, by substituting "late amino acids (C, F, M, T, W, and Y)" with "early amino acids (A, L, and V)" in a flavodoxin, we constructed a flavodoxin mutant and evaluated its characteristic properties. The major results showed that: (1) The flavodoxin mutant has structural characteristics similar to wild-type protein; (2) Although the semiquinone and hydroquinone flavodoxin mutants possess lower stability than the corresponding form of wild-type flavodoxin, the redox potential of double electron reduction Em,7 (fld) reached -360 mV, indicating that the flavodoxin mutant constituted solely by early amino acids can exert effective electron transfer activity.
有人提出，在氧化还原反应中，原始蛋白质利用有机辅因子的频率高于过渡金属。因此，对于仅由早期氨基酸和有机辅因子构成的蛋白质是否能进行电子转移活性进行实验验证是一项紧迫的挑战。在本文中，我们通过将黄素氧还蛋白中的“晚期氨基酸（C、F、M、T、W和Y）”替换为“早期氨基酸（A、L和V）”，构建了一个黄素氧还蛋白突变体并评估了其特性。主要结果表明：（1）黄素氧还蛋白突变体具有与野生型蛋白相似的结构特征；（2）尽管半醌型和对苯二酚型黄素氧还蛋白突变体的稳定性低于野生型黄素氧还蛋白的相应形式，但其双电子还原电位Em,7（fld）达到-360 mV，表明仅由早期氨基酸构成的黄素氧还蛋白突变体能够发挥有效的电子转移活性。
