Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th street, Miami, FL 33199, United States.
Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th street, Miami, FL 33199, United States.
J Hazard Mater. 2022 Mar 5;425:127765. doi: 10.1016/j.jhazmat.2021.127765. Epub 2021 Nov 16.
The presence of per and poly-fluoroalkyl substances (PFAS), commonly referred to as forever chemicals, in aquatic systems is a serious global health problem. While the remediation of PFAS from aqueous media has been extensively investigated, their interactions with and removal from biological systems have received far less attention. We report herein structural alterations to human serum albumin (HSA) upon addition of perfluoro(2-methyl-3-oxahexanoic) acid (Gen X) monitored by changes to the fluorescence and circular dichroism (CD) spectra of HSA. The equilibrium association constant for Gen X binding to HSA is 7( ± 1) × 10 M determined from changes in HSA fluorescence emission data during titration. Site-specific HSA binding fluorophores, 8-anilinonaphthalene-1-sulfonic acid (1,8-ANS), warfarin and dansyl-L-proline were used to investigate the specific binding sites of Gen X on HSA. A competitive displacement study yields association constants for Gen X to HSA at the 1,8-ANS, warfarin, and dansyl-L-proline binding sites to be 6.25 ( ± 0.5) × 10 M, 1.1 × 10 M, and 2.5( ± 0.2) × 10 M respectively. Addition of β-cyclodextrin (β-CD) and heptakis(6-deoxy-6-amino)-β-cyclodextrin heptahydrochloride to the HSA:Gen X complex leads to the effective extraction of Gen X from the complex with the return of HSA in its native form. Gen X also leads to displacement of site-specific binding fluorophores bound to HSA, while subsequent addition of β-CD extracts Gen X from HSA with the return of the characteristic fluorescence of the HSA bound site-specific agent. These results illustrate the strong and specific binding sites of Gen X on HSA and demonstrate the principles for the potential application of β-CD for the remediation of PFAS from biological systems.
全氟和多氟烷基物质（PFAS），通常称为永久性化学物质，存在于水生系统中是一个严重的全球健康问题。虽然已经广泛研究了从水介质中修复 PFAS，但它们与生物系统的相互作用及其去除却受到的关注较少。我们在此报告了添加全氟（2-甲基-3-氧杂己酸）（Gen X）后人血清白蛋白（HSA）的结构变化，通过 HSA 荧光和圆二色性（CD）光谱的变化来监测。从滴定过程中 HSA 荧光发射数据的变化确定 Gen X 与 HSA 结合的平衡缔合常数为 7(±1)×10 M。使用 8-苯胺-1-萘磺酸（1,8-ANS）、华法林和dansyl-L-脯氨酸等 HSA 结合荧光团来研究 Gen X 在 HSA 上的特异性结合位点。竞争置换研究得出 Gen X 与 HSA 在 1,8-ANS、华法林和 dansyl-L-脯氨酸结合位点的结合常数分别为 6.25(±0.5)×10 M、1.1×10 M 和 2.5(±0.2)×10 M。向 HSA:Gen X 复合物中添加β-环糊精（β-CD）和六（6-去氧-6-氨基）-β-环糊精六盐酸盐导致 Gen X 从复合物中有效提取，同时 HSA 恢复为天然形式。Gen X 还导致与 HSA 结合的特异性结合荧光团的置换，而随后添加的 β-CD 从 HSA 中提取 Gen X，同时恢复与 HSA 结合的特异性结合试剂的特征荧光。这些结果说明了 Gen X 与人血清白蛋白（HSA）之间的强特异性结合位点，并证明了使用β-CD 从生物系统中修复 PFAS 的潜在应用原理。
