血浆糖蛋白β2-GPI分子结构域与ox-LDL结合机制

Binding of glycoprotein β2-GPI with oxidized low density lipoprotein

摘要:

通过酵母重组P.rβ2-GPI-DV (β2糖蛋白I第5结构域) 蛋白的荧光、圆二色谱及分子对接模拟，分析血浆糖蛋白β2-GPI-DV分子结构域与ox-LDL的结合机制。SDS-PAGE、Western blotting验证重组蛋白 P.rβ2-GPI-DV表达正确性及纯度；荧光、圆二色光谱、分子对接模拟解析重组蛋白与oxLDL、oxLDL配体oxLig-1可能存在的结合机制和位点。SDS-PAGE、Western blotting显示，在12 kDa大小处有目的蛋白存在且与特异性抗体结合；荧光、圆二色谱的发色基团、二级结构的变化趋势及分子对接模拟结果揭示，P.rβ2-GPI-DV的Cys281-Lys-Asn-Lys-Glu-Lys-Lys287和Leu313-Ala-Phe-Trp316区域组成的活性口袋与oxLig-1的ω-COOH羧基是实现二者结合的关键。以上结果表明，β2-GPI通过其第5结构域 (DV) 的赖氨酸阳性区域与ox-LDL的ω-COOH基团识别结合，为血清中β2-GPI特异性结合ox-LDL的机制研究提供理论依据。

Abstract:

We analyzed the binding of P.rβ2-GPI-DV with ox-LDL by fluorescence, molecular simulation and circular dichroism. We used SDS-PAGE and Western blotting to identify the purity of P.rβ2-GPI-DV, fluorescence, circular dichroism spectroscopy and molecular docking simulation to analyze the binding between P.rβ2-GPI-DV and oxLDL. P.rβ2-GPI-DV was specifically recognized by anti-His antibody at 12 kDa position. The chromophoric groups, the changes of secondary structure and the molecular docking simulations revealed that the active pocket formed by Cys281-Lys-Asn-Lys-Glu-Lys-Lys287 and Leu313-Ala-Phe-Trp316 of P.rβ2-GPI-DV and the -COOH carboxyl of oxLig-1 were the key for binding. P.rβ2-GPI combined with ox-LDL via the fifth functional domain and the -COOH group. Our findings provide theoretical basis to further study the binding between β2-GPI and ox-LDL in serum.