Yano Yohko F, Uruga Tomoya, Tanida Hajime, Toyokawa Hidenori, Terada Yasuko, Takagaki Masafumi, Yamada Hironari
Synchrotron Light Life Science Center, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu-shi, Shiga 525-8577, Japan.
Langmuir. 2009 Jan 6;25(1):32-5. doi: 10.1021/la803235x.
Time-resolved X-ray reflectivity measurements for lysozyme (LSZ) adsorbed at an air/water interface were performed to study the mechanism of adsorption-induced protein unfolding. The time dependence of the density profile at the air/water interface revealed that the molecular conformation changed significantly during adsorption. Taking into account previous work using Fourier transform infrared (FTIR) spectroscopy, we propose that the LSZ molecules initially adsorbed on the air/water interface have a flat unfolded structure, forming antiparallel beta-sheets as a result of hydrophobic interactions with the gas phase. In contrast, as adsorption continues, a second layer forms in which the molecules have a very loose structure having random coils as a result of hydrophilic interactions with the hydrophilic groups that protrude from the first layer.
为了研究吸附诱导蛋白质展开的机制，我们对吸附在空气/水界面的溶菌酶（LSZ）进行了时间分辨X射线反射率测量。空气/水界面处密度分布的时间依赖性表明，吸附过程中分子构象发生了显著变化。考虑到之前使用傅里叶变换红外（FTIR）光谱的研究工作，我们提出，最初吸附在空气/水界面的LSZ分子具有扁平的展开结构，由于与气相的疏水相互作用而形成反平行β-折叠片层。相比之下，随着吸附的继续，形成了第二层，其中的分子具有非常松散的结构，由于与从第一层突出的亲水基团的亲水相互作用而具有无规卷曲。
