偶氮苯光开关的顺式状态通过与蛋白质表面的特定相互作用得以稳定。
The cis-state of an azobenzene photoswitch is stabilized through specific interactions with a protein surface.
作者信息
Korbus Michael, Backé Sarah, Meyer-Almes Franz-Josef
机构信息
Department of Chemical Engineering and Biotechnology, University of Applied Sciences Darmstadt, 64287, Darmstadt, Germany.
出版信息
J Mol Recognit. 2015 Mar;28(3):201-9. doi: 10.1002/jmr.2415. Epub 2015 Feb 9.
The photocontrol of protein function like enzyme activity has been the subject of many investigations to enable reversible and spatiotemporally defined cascading biochemical reactions without the need for separation in miniaturized and parallelized assay setups for academic and industrial applications. A photoswitchable amidohydrolase variant from Bordetella/Alcaligenes with the longest reported half-life (approximately 30 h) for the cis-state of the attached azobenzene group was chosen as a model system to dissect the underlying mechanism and molecular interactions that caused the enormous deceleration of the thermal cis-to-trans relaxation of the azobenzene photoswitch. A systematic site-directed mutagenesis study on the basis of molecular dynamics simulation data was employed to investigate enzyme and thermal cis-to-trans relaxation kinetics in dependence on selected amino acid substitution, which revealed a prominent histidine and a hydrophobic cluster as molecular determinants for the stabilization of the cis-isomer of the attached azobenzene moiety on the protein surface. The nature of the involved interactions consists of polar, hydrophobic, and possibly aromatic Π-Π contributions. The elucidated principles behind the stabilization of the cis-state of azobenzene derivatives on a protein surface can be exploited to design improved biologically inspired photoswitches. Moreover, the findings open the door to highly long-lived cis-states of azobenzene groups yielding improved bistable photoswitches that can be controlled by single light-pulses rather than continuous irradiation with UV light that causes potential photodamage to the employed biomolecules.
蛋白质功能(如酶活性)的光控一直是众多研究的主题,目的是在无需分离的情况下实现可逆且时空定义明确的级联生化反应,适用于学术和工业应用中的小型化及并行化分析设置。我们选择了一种来自博德特氏菌/产碱菌的可光开关酰胺水解酶变体作为模型系统,该变体所连接偶氮苯基团的顺式状态具有报道中最长的半衰期(约30小时),用于剖析导致偶氮苯光开关热顺 - 反弛豫大幅减速的潜在机制和分子相互作用。基于分子动力学模拟数据进行了系统的定点诱变研究,以考察依赖于选定氨基酸取代的酶和热顺 - 反弛豫动力学,结果揭示了一个突出的组氨酸和一个疏水簇是蛋白质表面上所连接偶氮苯部分顺式异构体稳定化的分子决定因素。所涉及相互作用的性质包括极性、疏水性以及可能的芳香族π - π贡献。偶氮苯衍生物在蛋白质表面顺式状态稳定化背后所阐明的原理可用于设计改进的受生物启发的光开关。此外,这些发现为偶氮苯基团的高度长寿命顺式状态打开了大门,从而产生改进的双稳态光开关,其可由单个光脉冲控制,而非通过对所使用生物分子可能造成光损伤的紫外光连续照射来控制。