Novel Probes Showing Specific Fluorescence Enhancement on Binding to a Hexahistidine Tag
作者:Mie Kamoto、Naoki Umezawa、Nobuki Kato、Tsunehiko Higuchi
DOI:10.1002/chem.200701896
日期:2008.9.8
The introduction of hexahistidine (His tag) is widely used as a tool for affinity purification of recombinant proteins, since the His tag binds selectively to nickel-nitrilotriacetic acid (Ni2+-NTA) complex. To develop efficient "turn-on" fluorescent probes for His-tagged proteins, we adopted a fluorophore displacement strategy, that is, we designed probes in which a hydroxycoumarin fluorophore is
六组氨酸(His标签)的引入被广泛用作重组蛋白亲和纯化的工具,因为His标签可选择性结合至镍-三三乙酸镍(Ni2 + -NTA)复合物。为了开发用于His标记蛋白的高效“开启”荧光探针,我们采用了荧光团置换策略,即,我们设计了其中羟基香豆素荧光团通过接头与金属-NTA部分相连的探针弱的分子内复合物,从而猝灭荧光。在存在与金属-NTA部分牢固结合的His标签的情况下,荧光团被置换,从而导致荧光显着增强。我们合成了一系列羟基香豆素,这些羟基香豆素被各种连接物修饰为NTA(NTAC配体),并研究了游离配体及其金属配合物的化学和光物理性质。从荧光猝灭的观点来看,Ni 2+和Co 2+是最好的金属。荧光光谱显示,pH 7.4水性缓冲液中NTAC的Ni2 +和Co2 +配合物的化学计量比为1:1。如预期的那样,这些复合物显示出弱的固有荧光,但是在pH 7.4水性缓冲液中添加带有His标记的肽(H-(H