Photochemical intermediates of Arabidopsis phototropin 2 LOV domains associated with conformational changes
Photochemical intermediates of Arabidopsis phototropin 2 LOV domains associated with conformational changes
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DOI：
10.1016/j.jmb.2007.06.035
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发表时间：
2007-08-31
影响因子：
5.6
通讯作者：
Terazima, Masahide
中科院分区：
文献类型：
--
作者：
Eitoku, Takeshi;Nakasone, Yusuke;Terazima, Masahide
利用时间分辨的瞬态光栅（TG）和瞬态透镜（TrL）方法研究了拟南芥光氧电压结构域2（LOV 2）的光化学反应.尽管加合物形成后吸收光谱没有变化，但LOV 2观察到了一个时间常数为9 ms的小体积膨胀过程。对于低-连接器，在293 K，观察到除了9英寸的体积膨胀过程和2毫秒的扩散系数变化的时间常数为140 LIS的体积收缩过程。反应中间物种的特征在于它们的热力学性质的基础上，如焓，热膨胀，和热容的变化。对于第一中间体（S390），这些性质的值类似于LOV 2和LOW-连接体的基态的那些。对于LOV 2-连接体的中间体，检测到相对大的热膨胀体积（0.09 cm（3）mol（-1）K-1）和正热容变化（4.7 kJ mol（-1）K-1）。这些特征被解释为结构波动和暴露的疏水残基的连接域，分别。LOV 1结构域的S390的焓变显著大于LOV 2或LOV 2-接头样品的变化。从这项研究的数据支持一个主要的构象变化的连接器区域的光化学反应的phototropin。(c)2007爱思唯尔有限公司保留所有权利。
The photochemical reactions of Arabidopsis phototropin 2 light- oxygen-voltage domain 2 (LOV2) with the linker region (LOV2-linker), without the linker (LOV2), and LOV1 were studied using the time-resolved transient grating (TG) and transient lens (TrL) methods. Although the absorption spectra did not change after the formation of the adduct species, a small volume expansion process with a time constant of 9 ms was observed for LOV2. For the LOW-linker, at 293 K, a volume contraction process with a time constant of 140 lis was observed in addition to a volume expansion process with 9 ins and the diffusion coefficient change with 2 ms. The reaction intermediate species were characterized on the basis of their thermodynamic properties, such as changes in enthalpy, thermal expansion, and heat capacity. For the first intermediate (S390), the values of these properties were similar to those of the ground state for both LOV2 and LOW-linker. A relatively large thermal expansion volume(0.09 cm(3) mol(-1) K-1) and a positive heat capacity change (4.7 kJ mol(-1) K-1) were detected for the intermediates of LOV2-linker. These characteristic features were interpreted in terms of structural fluctuation and exposure of hydrophobic residues in the linker domain, respectively. The enthalpy change Of S390 of the LOV1 domain was significantly greater than changes for the LOV2 or LOV2-linker samples. Data from this study support a major conformational change of the linker region in the photochemical reaction of phototropin. (c) 2007 Elsevier Ltd. All rights reserved.