Complex formation of bovine serum albumin with a poly(ethylene glycol) lipid conjugate
Complex formation of bovine serum albumin with a poly(ethylene glycol) lipid conjugate
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DOI：
10.1021/bm070116o
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发表时间：
2007-07-01
影响因子：
6.2
通讯作者：
Jauregi, Paula
中科院分区：
文献类型：
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作者：
Castelletto, Valeria;Krysmann, Marta;Jauregi, Paula
在这项工作中，我们报告了牛血清白蛋白（BSA）与聚（乙二醇）脂质共轭物（PEG（2000）-PE）在磷酸盐缓冲溶液（pH 7.4）中的自组装形成的复合物。研究了三组不同的样品。在每组样品中，BSA浓度保持固定（1、0.01或0.001重量% BSA），而PEG（2000）-PE浓度变化。动态光散射（DLS），流变学，和小角X射线散射（SAXS）用于研究样品与1重量%的BSA。DLS表明BSA/PEG（2000）-PE聚集体的尺寸介于BSA单体和PEG（2000）-PE胶束之间。流变学结果表明，BSA/PEG（2000）-PE复合物可能被相对致密的PEG-脂质壳所包围，而SAXS结果表明，耗尽力在复合物的稳定性中不起重要作用。通过圆二色性（CD）和紫外荧光光谱（UV）研究了含有0.01wt% BSA的样品。UV结果显示，在低浓度的PEG-脂质下，PEG（2000）-PE与BSA中的色氨酸（Trp）基团结合，而在高浓度的PEG-脂质下，Trp基团暴露于水。CD结果表明，色氨酸环境的变化发生与BSA二级结构元素的最小变化。最后，含有0.001重量% BSA的样品进行了研究zeta电位实验。结果表明，空间位阻作用对BSA/PEG（2000）-PE复合物的稳定性起重要作用。
In this work, we report the formation of complexes by self-assembly of bovine serum albumin (BSA) with a poly(ethylene glycol) lipid conjugate (PEG(2000)-PE) in phosphate saline buffer solution (pH 7.4). Three different sets of samples have been studied. The BSA concentration remained fixed (1, 0.01, or 0.001 wt % BSA) within each set of samples, while the PEG(2000)-PE concentration was varied. Dynamic light scattering (DLS), rheology, and small-angle X-ray scattering (SAXS) were used to study samples with 1 wt % BSA. DLS showed that BSA/PEG(2000)-PE aggregates have a size intermediate between a BSA monomer and a PEG(2000)-PE micelle. Rheology suggested that BSA/PEG(2000)-PE complexes might be surrounded by a relatively compact PEG-lipid shell, while SAXS results showed that depletion forces do not take an important role in the stabilization of the complexes. Samples containing 0.01 wt % BSA were studied by circular dichroism (CD) and ultraviolet fluorescence spectroscopy (UV). UV results showed that at low concentrations of PEG-lipid, PEG(2000)-PE binds to tryptophan (Trp) groups in BSA, while at high concentrations of PEG-lipid the Trp groups are exposed to water. CD results showed that changes in Trp environment take place with a minimal variation of the BSA secondary structure elements. Finally, samples containing 0.001 wt % BSA were studied by zeta-potential experiments. Results showed that steric interactions might play an important role in the stabilization of the BSA/PEG(2000)-PE complexes.