纳米塑料-脲酶蛋白冠的形成及特征

Formation and characteristics of protein corona formed by nanoplastics and urease

[目的]本研究旨在明确纳米塑料-脲酶蛋白冠的形成及对纳米塑料和脲酶的影响。[方法]以带正电、带负电、不带电的纳米塑料和质量浓度为0.05、0.20、0.50 mg·mL^(-1)的脲酶为试验材料,制备不同的纳米塑料-脲酶混悬液。根据纳米塑料对脲酶的吸附量和形貌特征变化,明确蛋白冠的形成。通过粗糙度、水合粒径、Zeta电位和脲酶构象、活性等指标分析,判定不同条件下蛋白冠的形成对纳米塑料表征及脲酶结构和活性的影响。[结果]不同电性纳米塑料对各浓度脲酶均产生吸附,形成蛋白冠;随着脲酶质量浓度增加,蛋白冠的颗粒粒径和表面粗糙度增加;带正电纳米塑料-脲酶蛋白冠与原纳米塑料差异最显著,且显著抑制脲酶活性;当脲酶质量浓度为0.05 mg·mL^(-1)时,蛋白冠的形成会导致脲酶构象发生明显变化,表现为β-折叠结构含量显著下降,无规则结构含量明显上升的特点。[结论]3种电性纳米塑料均可以和脲酶形成蛋白冠,不同程度降低其分散性和稳定性。蛋白冠对纳米塑料和脲酶的影响强度与纳米塑料的带电性和脲酶质量浓度密切相关。

[Objectives]This study aimed to clarify the formation of protein corona by nanoplastics and urease,and its effects on nanoplastics and urease.[Methods]Different nanoplastics-urease suspensions were prepared by using positively charged,negatively charged and uncharged nanoplastics and urease with concentrations of 0.05,0.20 and 0.50 mg·mL^(-1)as test materials.According to the adsorption amount of urease and the changes in morphological characteristics of nanoplastics,the formation of protein corona was clarified.Through the analysis of roughness,hydrate particle size,zeta potential,urease conformation,activity and other indicators,the effect of protein corona formation on the characterization of nanoplastics and urease structure and activity under different conditions was determined.[Results]Differently charged nanoplastics adsorbed urease with all concentrations to form protein corona.With the increase of urease mass concentrations,the particle size and surface roughness of the protein corona increased;the protein corona formed by positively charged nanoplastics and urease showed the most significant difference from the original nanoplastics,and the urease activity was significantly inhibited.When the urease mass concentrations was 0.05 mg·mL^(-1),the formation of protein corona would lead to significant changes in urease conformation,which was characterized by a significant decrease in the content ofβ-folded structure and a significant increase in the content of irregular structure.[Conclusions]Three nanoplastics in our experiment would form protein corona with urease,reducing their dispersion and stability to varying degrees.The strength of the effect of protein corona on nanoplastics and urease was closely related to the chargeability and urease mass concentrations of nanoplastics.