Tyrosinase enzyme Langmuir monolayer: Surface chemistry and spectroscopic study
Tyrosinase enzyme Langmuir monolayer: Surface chemistry and spectroscopic study
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DOI：
10.1016/j.jcis.2019.12.118
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发表时间：
2020-03-22
影响因子：
9.9
通讯作者：
Leblanc, Roger M.
中科院分区：
文献类型：
--
作者：
Paudyal, Suraj;Sharma, Shiv K.;Leblanc, Roger M.
本文研究了酪氨酸酶Langmuir单分子膜在空气-水界面上的表面化学性质，在亚相中使用氯化钠来诱导酶的表面活性。利用表面化学实验研究了酪氨酸酶单分子膜的表面堆积和稳定性，同时利用光谱分析研究了酶的构象。压缩-减压循环实验和不同表面压力下的稳定性测试结果表明，酪氨酸酶在空气-水界面形成了稳定的流体膜。在不同表面压力下的紫外-可见吸收光谱和荧光光谱的测量结果表明，Langmuir单分子膜具有良好的均匀性，没有证据表明在压缩过程中的聚集体。为了深入了解酪氨酸酶的构象，使用Langmuir单层p偏振红外反射吸收光谱。结果发现，在高表面压力下，主要的二级结构是β-折叠，而在较低的表面压力下，α-螺旋和β-折叠都存在。通过将10 mN·m（-1）的Langmuir单层转移到固体石英载体（Langmuir-Blodgett膜，LB膜）上获得圆二色性光谱，这表明存在的主要构象是α-螺旋。使用原子力显微镜从固定化LB膜获得图像，其显示平均厚度为3至4 nm的均匀和规则的沉积。(C)2019爱思唯尔公司All rights reserved.
This study investigates the surface chemistry properties of the tyrosinase enzyme Langmuir monolayer at air-aqueous interface using sodium chloride in the subphase to induce the surface activity of the enzyme. Investigation of surface packing and stability of the tyrosinase Langmuir monolayer were performed using surface chemistry experiments while spectroscopic analysis was done to study enzyme conformation. It was found that the tyrosinase enzyme forms a fluid film at air-aqueous interface with good stability as shown by compression-decompression cycles experiments and stability measurements at various surface pressures. UV-vis absorption and fluorescence measurements at different surface pres-sures revealed that the Langmuir monolayer has good homogeneity with no evidence of aggregates during compression. To gain insight on the conformation of tyrosinase Langmuir monolayer p-polarized infrared-reflection absorption spectroscopy was used. It was found that at high surface pressures the predominant secondary structures were beta-sheets while at lower surface pressure both alpha -helices and beta-sheets were present. The circular dichroism spectra were obtained by transferring the Langmuir mono-layer at 10 mN.m(-1) to a solid quartz support (Langmuir-Blodgett film, LB film), which showed that the major conformation present were alpha-helices. Images from the immobilized LB films were obtained using atomic force microscopy which showed homogenous and regular deposition with a mean thickness ranging from 3 to 4 nm. (C) 2019 Elsevier Inc. All rights reserved.