Max Planck Institute for Polymer Research, Mainz, Germany.
Biophys J. 2010 Nov 3;99(9):3020-8. doi: 10.1016/j.bpj.2010.08.022.
Myelin basic protein (MBP) is predominantly found in the membranes of the myelin sheath of the central nervous system and is involved in important protein-protein and protein-lipid interactions in vivo and in vitro. Furthermore, divalent transition metal ions, especially Zn(2+) and Cu(2+), seem to directly affect the MBP-mediated formation and stabilization of the myelin sheath of the central nervous system. MBP belongs to the realm of intrinsically disordered proteins, and only fragmentary information is available regarding its partial structure(s) or supramolecular arrangements. Here, using standard continuous wave and modern pulse electron paramagnetic resonance methods, as well as dynamic light scattering, we demonstrate the uptake and specific coordination of two Cu(2+) atoms or one Zn(2+) atom per MBP molecule in solution. In the presence of phosphates, further addition of divalent metal ions above a characteristic threshold of four Cu(2+) atoms or two Zn(2+) atoms per MBP molecule leads to the formation of large MBP aggregates within the protein solution. In vivo, MBP-MBP interactions may thus be mediated by divalent cations.
髓鞘碱性蛋白 (MBP) 主要存在于中枢神经系统髓鞘的膜中，参与体内和体外重要的蛋白质-蛋白质和蛋白质-脂质相互作用。此外，二价过渡金属离子，特别是 Zn(2+) 和 Cu(2+)，似乎直接影响中枢神经系统 MBP 介导的髓鞘形成和稳定。MBP 属于固有无序蛋白质的范畴，关于其部分结构或超分子排列只有零碎的信息。在这里，我们使用标准的连续波和现代脉冲电子顺磁共振方法以及动态光散射，证明了在溶液中每个 MBP 分子中摄取和特定配位两个 Cu(2+)原子或一个 Zn(2+)原子。在存在磷酸盐的情况下，超过每个 MBP 分子四个 Cu(2+)原子或两个 Zn(2+)原子的特征阈值进一步添加二价金属离子会导致蛋白质溶液中形成大的 MBP 聚集体。因此，在体内，MBP-MBP 相互作用可能由二价阳离子介导。
