Kinetics of switchable proton escape from a proton-wire within green fluorescence protein
Kinetics of switchable proton escape from a proton-wire within green fluorescence protein
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DOI：
10.1021/jp071403p
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发表时间：
2007-07-12
影响因子：
3.3
通讯作者：
Agmon, Noam
中科院分区：
文献类型：
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作者：
Agmon, Noam
绿色荧光蛋白（GFP）的酸性形式的发射随时间和温度从T（-1/2）到T（-3/2）渐近造成的变化。结果表明，蛋白质中质子扩散的模型沿蛋白质内的一维氢键网络，开关（THR203）允许质子逃脱，该数据允许质子逃脱。从模型与实验的比较中，我们获得了从发色团中质子解离的速率参数（显示反向温度效应），质子缔合常数与其扩散常数（无温度效应）的比率，以及时间开关打开（具有明显的Arrhenius依赖性）。因此，质子解离具有较小的负激活能（分配给带有H3O+的阴离子发色团的复合物），而开关具有较大的阳性激活能（分配给THR203侧链旋转）。质子迁移可能是GFP中几个质子一致运动的结果。
The emission from the acidic form of the green fluorescence protein (GFP) changes with increasing time and temperature from t(-1/2) to t(-3/2) asymptotics. It is shown that a model of proton diffusion along a one-dimensional hydrogen-bond network within the protein, with a switch (Thr203) allowing for proton escape, explains the data quantitatively. From a comparison of the model with experiment, we obtain the rate parameters for proton dissociation from the chromophore (showing an inverse temperature effect), the ratio of the proton association constant squared to its diffusion constant (exhibiting no temperature effect), and the time constant for switch opening (with a significant Arrhenius dependence). Thus, proton dissociation has a small negative activation energy (assigned to a complex of the anionic chromophore with H3O+), whereas the switch has a large positive activation energy (assigned to Thr203 side-chain rotation). Proton migration is possibly the outcome of the concerted motion of several protons within GFP.