Department of Photonics, MTA TTK MFA, Budapest, Hungary.
Anal Chem. 2013 Jun 4;85(11):5382-9. doi: 10.1021/ac3034322. Epub 2013 May 16.
The surface adsorption of the protein flagellin was followed in situ using optical waveguide lightmode spectroscopy (OWLS). Flagellin did not show significant adsorption on a hydrophilic waveguide, but very rapidly formed a dense monolayer on a hydrophobic (silanized) surface. The homogeneous and isotropic optical layer model, which has hitherto been generally applied in OWLS data interpretation for adsorbed protein films, failed to characterize the flagellin layer, but it could be successfully modeled as an uniaxial thin film. This anisotropic modeling revealed a significant positive birefringence in the layer, suggesting oriented protein adsorption. The adsorbed flagellin orientation was further evidenced by monitoring the surface adsorption of truncated flagellin variants, in which the terminal protein regions or the central (D3) domain were removed. Without the terminal regions the protein adsorption was much slower and the resulting films were significantly less birefringent, implying that intact flagellin adsorbs on the hydrophobic surface via its terminal regions.
使用光波导光模谱（OWLS）对蛋白质鞭毛蛋白的表面吸附进行了原位跟踪。鞭毛蛋白在亲水波导上没有明显的吸附，但在疏水（硅烷化）表面上非常迅速地形成了致密的单层。迄今为止，在用于吸附蛋白膜的 OWLS 数据分析中广泛应用的均匀各向同性光学层模型无法描述鞭毛蛋白层，但可以成功地建模为单轴薄膜。这种各向异性建模显示出该层具有显著的正双折射，表明蛋白具有定向吸附性。通过监测截短鞭毛蛋白变体的表面吸附，进一步证明了吸附的鞭毛蛋白的取向，其中去除了末端蛋白区域或中央（D3）结构域。没有末端区域，蛋白吸附速度会慢很多，得到的薄膜的双折射也明显降低，这意味着完整的鞭毛蛋白通过其末端区域在疏水表面上吸附。
