Department of Inorganic Chemistry, Maria Curie-Sklodowska University, M. C. Sklodowska Sq. 2, 20-031 Lublin, Poland.
Spectrochim Acta A Mol Biomol Spectrosc. 2017 Sep 5;184:262-269. doi: 10.1016/j.saa.2017.05.014. Epub 2017 May 11.
The binding affinity between vitamin B12 (VitB12) and bovine serum albumin (BSA) has been investigated in aqueous solution at pH=7.4, employing UV-vis absorption and steady-state, synchronous and three-dimensional fluorescence spectra techniques. Representative effects noted for BSA intrinsic fluorescence resulting from the interactions with VitB12 confirm the formation of π-π stacked non-covalent and non-fluorescent complexes in the system VitB12-BSA. All the determined parameters, the binding, fluorescence quenching and bimolecular quenching rate constants (of the order of 10Lmol, 10Lmol and 10Lmols, respectively), as well as Förster resonance energy transfer parameters validate the mechanism of static quenching. The interaction with VitB12 induces folding of the polypeptide chains around Trp residues of BSA, resulting in a more hydrophobic surrounding. Presented outcomes suggest that the addition of VitB12 can lead to the more organized BSA conformation and its more folded tertiary structure, what could influence the physiological functions of bovine serum albumin, notably in case of its overuse or abnormal metabolism.
在 pH=7.4 的水溶液中，采用紫外-可见吸收光谱、稳态、同步和三维荧光光谱技术研究了维生素 B12（VitB12）与牛血清白蛋白（BSA）之间的结合亲和力。BSA 内源荧光与 VitB12 相互作用所产生的代表性效应证实了在 VitB12-BSA 体系中形成了π-π堆积的非共价和非荧光复合物。所有确定的参数，包括结合、荧光猝灭和双分子猝灭速率常数（分别为 10Lmol、10Lmol 和 10Lmols）以及福斯特共振能量转移参数，都验证了静态猝灭的机制。与 VitB12 的相互作用诱导 BSA 多肽链围绕色氨酸残基折叠，导致更疏水的环境。目前的结果表明，添加 VitB12 可以导致 BSA 构象更加有序，其三级结构更加折叠，这可能会影响牛血清白蛋白的生理功能，特别是在其过度使用或异常代谢的情况下。
