A competitive low-affinity binding model for determining the mutual and specific sites of two ligands on protein.
A competitive low-affinity binding model for determining the mutual and specific sites of two ligands on protein.
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DOI：
10.1016/j.jpba.2004.12.037
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发表时间：
2005-07
影响因子：
3.4
通讯作者：
Guoyun Bai;Yanfang Cui;Yunhuang Yang;C. Ye;Maili Liu
中科院分区：
文献类型：
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作者：
Guoyun Bai;Yanfang Cui;Yunhuang Yang;C. Ye;Maili Liu
提出了一个竞争性低亲和力结合模型，用于确定两个配体(A，B)在蛋白质(P)上的相互(重叠)和特定结合部位的数目。要使用该模型，需要在三元体系(A-B-P)中加入配体A或B进行滴定实验，并监测光谱参数的变化。将滴定曲线与所提出的模型进行拟合，可以得到两种配体在蛋白质上的相互结合部位和特异结合部位。模型以人血清白蛋白(HSA)为受体，托美汀(TOL)和水杨酸(SAL)为配体。在滴定过程中，在500 MHz的核磁共振波谱仪上测量了质子纵向驰豫速率(R1)，并用来推导相互结合的位置。结果发现，在人血清白蛋白表面32±4个SAL和28±2个TOL的结合部位中，有17±5个相互作用部位。这一结果表明，尽管人血清白蛋白与大多数配体有很大的结合能力，但仍有相当数量的低亲和力结合位点具有结构选择性。
A competitive low-affinity binding model was proposed for determining the number of mutual (overlapped) and specific binding sites of two ligands (A, B) on a protein (P). To use the model, one needs to carry out a titration experiment by adding either ligand A or B into a three-component system (A–B–P), and to monitor the spectroscopic parameter changes. Fitting the titration curve to the proposed model, one can get the mutual and specific binding sites of the two ligands on the protein. The model was examined by using human serum albumin (HSA) as a receptor and tolmetin (TOL) and salicylic acid (SAL) as ligands. Proton longitudinal relaxation rates (R1) were measured on a 500-MHz NMR spectrometer during the titration and used to derive the mutual binding sites. It was found that among the binding sites of 32±4 for SAL and 28±2 for TOL on HSA, there were 17±5 mutual sites for the two ligands. This result indicates that, although HSA has large binding capacities for most ligands, there are still a reasonable amount of the low-affinity binding sites that are structure selective.