Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
Molecules. 2021 Oct 29;26(21):6565. doi: 10.3390/molecules26216565.
The binding interactions of bovine serum albumin (BSA) with tetraphenylborate ions ([B(Ph)]) have been investigated by a set of experimental methods (isothermal titration calorimetry, steady-state fluorescence spectroscopy, differential scanning calorimetry and circular dichroism spectroscopy) and molecular dynamics-based computational approaches. Two sets of structurally distinctive binding sites in BSA were found under the experimental conditions (10 mM cacodylate buffer, pH 7, 298.15 K). The obtained results, supported by the competitive interactions experiments of SDS with [B(Ph)] for BSA, enabled us to find the potential binding sites in BSA. The first site is located in the subdomain I A of the protein and binds two [B(Ph)] ions (log = 7.09 ± 0.10; Δ = -9.67 ± 0.14 kcal mol; Δ = -3.14 ± 0.12 kcal mol; TΔ = -6.53 kcal mol), whereas the second site is localized in the subdomain III A and binds five ions (log = 5.39 ± 0.06; Δ = -7.35 ± 0.09 kcal mol; Δ = 4.00 ± 0.14 kcal mol; TΔ = 11.3 kcal mol). The formation of the {[B(Ph)]}-BSA complex results in an increase in the thermal stability of the alfa-helical content, correlating with the saturation of the particular BSA binding sites, thus hindering its thermal unfolding.
牛血清白蛋白（BSA）与四苯硼酸盐离子（[B(Ph)]）的结合相互作用已通过一系列实验方法（等温热滴定法、稳态荧光光谱法、差示扫描量热法和圆二色光谱法）和基于分子动力学的计算方法进行了研究。在实验条件下（10 mM 二甲胂酸盐缓冲液，pH 7，298.15 K）发现了 BSA 中两个结构独特的结合位点。结合 SDS 与 [B(Ph)] 对 BSA 的竞争相互作用实验的结果，使我们能够找到 BSA 中的潜在结合位点。第一个结合位点位于蛋白质的子域 I A 中，结合两个 [B(Ph)] 离子（log = 7.09 ± 0.10；Δ = -9.67 ± 0.14 kcal mol；Δ = -3.14 ± 0.12 kcal mol；TΔ = -6.53 kcal mol），而第二个结合位点位于子域 III A 中，结合五个离子（log = 5.39 ± 0.06；Δ = -7.35 ± 0.09 kcal mol；Δ = 4.00 ± 0.14 kcal mol；TΔ = 11.3 kcal mol）。[B(Ph)]-BSA 配合物的形成导致阿尔法螺旋含量的热稳定性增加，与特定 BSA 结合位点的饱和相关，从而阻碍其热解折叠。
