Interactions of Perfluorooctanesulfonate and 6:2 Chlorinated Polyfluorinated Ether Sulfonate with Human Serum Albumin: A Comparative Study
Interactions of Perfluorooctanesulfonate and 6:2 Chlorinated Polyfluorinated Ether Sulfonate with Human Serum Albumin: A Comparative Study
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全氟辛烷磺酸盐和6:2氯化多氟醚磺酸盐与人血清白蛋白的相互作用：比较研究
DOI：
10.1021/acs.chemrestox.0c00075
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发表时间：
2020
影响因子：
4.1
通讯作者：
Dai Jiayin
中科院分区：
文献类型：
--
作者：
Sheng Nan;Wang Jinghua;Guo Yong;Wang Jianshe;Dai Jiayin
6：2氯化多氟醚磺酸(6：2Cl-PFESA)与全氟辛烷磺酸盐(PFOS)结构相似，是中国人群中发现的第三大多氟烷基/全氟烷基物质。研究表明，与全氟辛烷磺酸相比，6：2氯-全氟辛烷磺酸具有更强的生物蓄积和毒理潜力，因此引起了相当大的环境关注。采用体外和硅胶法研究了全氟辛烷磺酸和6：2Cl-全氟辛烷磺酸与人血清白蛋白(HSA)的结合特性。在细胞摄取实验中，在培养液中添加人血清白蛋白抑制了全氟辛烷磺酸和6：2氯-全氟辛烷磺酸向细胞内的扩散。加入0.5、10和200μM HSA后，细胞内全氟辛烷磺酸浓度分别下降21.4%、78.1%和92.8%，6：2氯-全氟辛酸浓度分别下降28.4%、84.4%和93.9%。加入2 0 0μM HSA后，全氟辛烷磺酸与6：2氯全氟辛烷磺酸的结合力差异无统计学意义，但加入0.5和10μM人血清白蛋白后，细胞内6：2氯全氟辛烷磺酸与人血清白蛋白的结合力显著低于全氟辛烷磺酸，提示6：2氯全氟辛烷与人血清白蛋白的结合能力强于全氟辛烷磺酸。超滤离心法还表明，6：2Cl-全氟辛酸(Kd=16.7μM)比全氟辛烷磺酸(Kd=30.7μM)对人血清白蛋白具有更高的亲和力，但两者的结合摩尔比相似，1 M人血清白蛋白与3~4M全氟辛烷磺酸/6：2氯全氟辛酸结合。限制性蛋白水解法进一步鉴定出与全氟辛烷磺酸(肽II，氨基酸189-457)和6：2氯-全氟辛烷磺酸(肽I，氨基酸39-310)结合的核心HSA多肽。利用纯化的核心肽，6：2Cl-PFESA与多肽I和II的结合亲和力均强于全氟辛烷磺酸。结合模式表明，6：2Cl-PFESA中的氯原子和氧原子可能是导致其优先结合Sulow位点I而不是Trp214或Sulow位点II的原因，后者是全氟辛烷磺酸的最佳结合位点。总体而言，6：2Cl-PFESA与人血清白蛋白的结合亲和力较强，可能是其生物蓄积潜力高于全氟辛烷磺酸的原因之一。
6:2 Chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) possesses a similar structure to perfluorooctanesulfonate (PFOS) and is the third most important polyfluoroalkyl/perfluoroalkyl substance (PFAS) found in the general population of China. Studies have indicated that 6:2 Cl-PFESA exhibits a stronger bioaccumulative and toxicological potential than PFOS and is thus of considerable environmental concern. Here, the binding characteristics of PFOS and 6:2 Cl-PFESA to human serum albumin (HSA) were explored based onin vitroandin silicomethods. In the cell uptake assays, supplementation of HSA in the culture medium hindered diffusion of PFOS and 6:2 Cl-PFESA from the medium into cells. With the addition of 0.5, 10, and 200 μM HSA in the culture medium, the PFOS concentration in cells decreased by 21.4%, 78.1%, and 92.8%, whereas the 6:2 Cl-PFESA concentration in cells decreased by 28.4%, 84.4%, and 93.9%, respectively. Although no statistically significant difference between the reduction of PFOS and 6:2 Cl-PFESA was observed with 200 μM HSA in medium, the significant decrease in cellular 6:2 Cl-PFESA than PFOS after addition of 0.5 and 10 μM HSA implied that 6:2 Cl-PFESA had a stronger binding affinity than PFOS to HSA. Ultrafiltration centrifugation also suggested that 6:2 Cl-PFESA (Kd= 16.7 μM) had a higher affinity than PFOS (Kd= 30.7 μM) to HSA, though the binding molar ratios were similar, with 1 M HSA binding to 3–4 M PFOS/6:2 Cl-PFESA. Limited proteolysis further identified the core HSA peptides that bind to PFOS (peptide II, aa 189–457) and 6:2 Cl-PFESA (peptide I, aa 39–310). Using purified core peptides, 6:2 Cl-PFESA showed a stronger binding affinity than PFOS to both peptides I and II. The binding modes indicated that the chlorine and oxygen atoms in 6:2 Cl-PFESA were likely responsible for its preferential binding to Sudlow site I than to Trp214 or Sudlow site II, with the latter being the optimal binding site for PFOS. Overall, the stronger binding affinity of 6:2 Cl-PFESA to HSA may contribute to its higher bioaccumulation potential than PFOS.