Key Laboratory of Estuarine Ecological Security and Environmental Health, Tan Kah Kee College, Xiamen University, Zhangzhou 363105, PR China.
State Key Laboratory of Marine Environmental Sciences of China (Xiamen University), College of Environment and Ecology, Xiamen University, Xiamen 361102, Fujian Province, PR China.
Talanta. 2018 Aug 15;186:497-505. doi: 10.1016/j.talanta.2018.04.066. Epub 2018 Apr 22.
The interactions of pyrene (Pyr) and/or 1-hydroxypyrene (1-OHPyr) with bovine serum albumin (BSA) in binary and ternary systems were investigated using the excitation-emission matrix (EEM)-parallel factor analysis (PARAFAC) method combined with fluorescence quenching analysis and the molecular docking method. The results showed that the PARAFAC approach could be used to decompose the EEM spectra of Pyr, 1-OHPyr, and BSA in the binary and ternary systems. The binding constants of Pyr and 1-OHPyr with BSA increased from 1.01 × 10 and 1.62 × 10 L mol to 2.09 × 10 and 1.86 × 10 L mol in the ternary systems compared with the binary systems, respectively. Molecular docking revealed that in both binary and ternary systems, Pyr was bound between II A and III A regions of BSA, whereas 1-OHPyr was located in the I B region. Van der Waals forces dominated the formation of the BSA-Pyr complexes; however, for BSA-1-OHPyr complexes, in addition to Van der Waals forces, hydrogen bonds also played an important role in their binding as a hydrogen bond formed between 1-OHP and the amino residue of BSA. Moreover, the coexistence of Pyr and 1-OHPyr aggravated the conformation changes of BSA and led to a prominent decrease in the hydrophobicity of the micro-environment around tryptophan (TRP) residues. 1-OHPyr has a more severe influence on BSA conformation than Pyr in the ternary systems. This study will help to understand the combined effects of PAHs and their hydroxyl metabolites on proteins at the molecular level.
采用同步荧光光谱结合荧光猝灭分析和分子对接技术，利用激发-发射矩阵（EEM）-平行因子分析（PARAFAC）方法研究了苊（Pyr）和/或 1-羟苊（1-OHPyr）在二元和三元体系中与牛血清白蛋白（BSA）的相互作用。结果表明，PARAFAC 方法可用于分解二元和三元体系中 Pyr、1-OHPyr 和 BSA 的 EEM 光谱。与二元体系相比，Pyr 和 1-OHPyr 与 BSA 的结合常数分别从 1.01×10 和 1.62×10 L/mol 增加到 2.09×10 和 1.86×10 L/mol。分子对接表明，在二元和三元体系中，Pyr 均结合在 BSA 的 II A 和 III A 区域之间，而 1-OHPyr 则位于 I B 区域。在二元和三元体系中，范德华力均主导 BSA-Pyr 复合物的形成；然而，对于 BSA-1-OHPyr 复合物，除了范德华力之外，氢键也在其结合中起重要作用，因为 1-OHP 与 BSA 的氨基酸残基之间形成了氢键。此外，Pyr 和 1-OHPyr 的共存加剧了 BSA 的构象变化，导致色氨酸（TRP）残基周围微环境的疏水性显著降低。在三元体系中，1-OHPyr 对 BSA 构象的影响比 Pyr 更严重。该研究将有助于在分子水平上理解多环芳烃及其羟基代谢物对蛋白质的联合作用。
