Interactions of human serum albumin with retinoic acid, retinal and retinyl acetate
Interactions of human serum albumin with retinoic acid, retinal and retinyl acetate
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DOI：
10.1016/j.bcp.2006.11.023
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发表时间：
2007-03-15
影响因子：
5.8
通讯作者：
Karnaukhova, Elena
中科院分区：
文献类型：
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作者：
Karnaukhova, Elena
人血清白蛋白（HSA）是一种主要的血浆蛋白和血浆源性治疗药物，与多种药物和天然血浆代谢物相互作用。本研究采用紫外-可见吸收光谱、荧光光谱和圆二色性（CD）研究了HSA与亲脂小分子全反式维甲酸（RA）、全反式视黄醛（retinal， RAL）和全反式视黄酯（RAC）的相互作用。本文的重点是通过可见CD研究HSA和RA之间的相互作用。由于RAL和RAC在结构上与RA相同，因此本研究中使用了RAL和RAC来阐明末端官能团对复合物形成的重要性。我们的数据表明，RA特异性地与HSA结合在一个稳定的非共价复合物中，至少在两个内部结合位点具有接近但不同的亲和力。在用RA滴定HSA后，可见CD光谱清楚地表明在350 nm左右出现了明确的诱导阳性棉花效应（CE）。在配体与蛋白质的比值为0.8之后，直至饱和（2.0），CD呈现出两条相反的谱带，表明蛋白质内部的发色团分子之间存在激子偶联。荧光猝灭数据表明RA的主要结合位点接近色氨酸（W-214）。RAC与HSA的关联较弱，其化学计量接近RA，而RAL与HSA的相互作用在多个位点进行非特异性。与RA相反，HSA与RAC和RAL的加合物没有表现出任何诱导手性，这表明尽管它们与RA的结构高度相似，但这两种化合物似乎都没有占据内部结合位点，而是与蛋白质外部结合。Elsevier Inc.出版。
Human serum albumin (HSA), a major plasma protein and plasma-derived therapeutic, interacts with a wide variety of drugs and native plasma metabolites. In this study the interactions between HSA and small lipophilic molecules all-trans retinoic acid (RA), all-trans retinaldehyde (retinal, RAL) and all-trans retinyl acetate (RAC) were investigated by UV-vis absorption spectroscopy, fluorescence spectroscopy and circular dichroism (CD). This paper focuses on investigation of the interactions between HSA and RA by the visible CD. RAL and RAC were used in this study due to their structural identity to RA to elucidate the importance of the end functional group for the complex formation. Our data demonstrate that RA specifically binds to HSA in a stable non-covalent complex at least at two internal binding sites with close but distinct affinities. Upon titration of HSA with RA, visible CD spectra clearly demonstrate the appearance of a well-defined induced positive Cotton Effect (CE) around 350 nm. Beyond ligand-to-protein ratio of 0.8 and up to saturation (2.0), CD exhibits two major bands of opposite signs, suggesting exciton coupling between the chromophore molecules in the protein interior. The fluorescence quenching data suggest proximity of the primary RA binding site to tryptophan (W-214). RAC shows a weak association with HSA with stoichiometry close to that of RA, while interactions of RAL with HSA proceed non-specifically at multiple sites. Contrary to RA, the adducts of HSA with RAC and RAL do not show any induced chirality, thus indicating that despite their high structural similarity to RA, both compounds do not appear to occupy the internal binding sites, but associate with the protein exterior. Published by Elsevier Inc.