Department of Biophysics of Environmental Pollution, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland.
Department of Cytobiochemistry, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland.
Int J Mol Sci. 2020 May 30;21(11):3926. doi: 10.3390/ijms21113926.
Brominated flame retardants (BFRs) have been using to reduce the flammability of plastics contained in many products, such as household articles, furniture, mattresses, textiles or insulation. Considering the fact that these compounds may be released into the environment leading to the exposure of living organisms, it is necessary to study their possible effects and mechanisms of action. Proteins play a crucial role in all biological processes. For this reason, a simple model of human serum albumin (HSA) was chosen to study the mechanism of BFRs' effect on proteins. The study determined interactions between selected BFRs, i.e., tetrabromobisphenol A (TBBPA), tetrabromobisphenol S (TBBPS), 2,4-dibromophenol (2,4-DBP), 2,4,6-tribromophenol (2,4,6-TBP) and pentabromophenol (PBP), and HSA by measurement of fluorescence of intrinsic tryptophan and absorbance of circular dichroism (CD). In addition, in order to understand the possible effect of these compounds in their native environment, the effect of BFRs on membrane proteins of human erythrocytes (red blood cells, RBCs) was also assessed. Among bromophenols, PBP had the strongest oxidative effect on RBC membrane, and 2,4-DBP demonstrated the weakest fluorescence-quenching effect of both membrane tryptophan and HSA. By contrast to PBP, 2,4-DBP and 2,4,6-TBP caused spatial changes of HSA. We have observed that among all analyzed BFRs, TBBPA caused the strongest oxidation of RBC membrane proteins and the model HSA protein, causing reduction of fluorescence of tryptophan contained in them. TBBPA also changed albumin conformation properties, leading to impairment of the α-helix structure. However, TBBPS had the weakest oxidative effect on proteins among studied BFRs and did not affect the secondary structure of HSA.
溴系阻燃剂（BFRs）被广泛用于降低许多产品中塑料的可燃性，如家用物品、家具、床垫、纺织品或绝缘材料。考虑到这些化合物可能会释放到环境中，从而使生物体暴露在其中，因此有必要研究它们可能产生的影响和作用机制。蛋白质在所有生物过程中都起着至关重要的作用。出于这个原因，选择人血清白蛋白（HSA）作为一种简单的模型来研究 BFRs 对蛋白质的作用机制。该研究确定了选定的 BFRs（即四溴双酚 A（TBBPA）、四溴双酚 S（TBBPS）、2,4-二溴苯酚（2,4-DBP）、2,4,6-三溴苯酚（2,4,6-TBP）和五溴苯酚（PBP）与 HSA 之间的相互作用，通过测量内源色氨酸的荧光和圆二色性（CD）的吸光度来实现。此外，为了了解这些化合物在其天然环境中的可能影响，还评估了 BFRs 对人红细胞（红细胞，RBC）膜蛋白的影响。在溴酚中，PBP 对 RBC 膜具有最强的氧化作用，而 2,4-DBP 对膜色氨酸和 HSA 的荧光猝灭作用最弱。与 PBP 相反，2,4-DBP 和 2,4,6-TBP 导致 HSA 的空间构象发生变化。我们观察到，在所分析的所有 BFRs 中，TBBPA 对 RBC 膜蛋白和模型 HSA 蛋白的氧化作用最强，导致其中色氨酸的荧光减弱。TBBPA 还改变了白蛋白构象特性，导致α-螺旋结构受损。然而，TBBPS 在研究的 BFRs 中对蛋白质的氧化作用最弱，并且不影响 HSA 的二级结构。
