The subsequent effect of interaction between Co(2+) and human serum albumin or bovine serum albumin.
The subsequent effect of interaction between Co(2+) and human serum albumin or bovine serum albumin.
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DOI：
10.1016/s0162-0134(01)00195-7
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发表时间：
2001-06
影响因子：
3.9
通讯作者：
H. Liang;J. Huang;C. Tu;M. Zhang;Y. Zhou;P. Shen
中科院分区：
文献类型：
--
作者：
H. Liang;J. Huang;C. Tu;M. Zhang;Y. Zhou;P. Shen
在生理pH为7.43的条件下，Co(II)与人血清白蛋白(HSA)或牛血清白蛋白(BSA)的相互作用有明显的滞后效应，表明Co(II)与人血清白蛋白(HSA)或牛血清白蛋白(BSA)的结合可能导致HSA或BSA从对Co(II)较弱的亲和力构象向较强亲和力构象(A-B转变)的缓慢转变。测量了该转变的速率常数和活化参数，并对其进行了讨论。推测这种构象转变可能是由于第一个Co(II)离子与N-末端残基1-3的多肽片段结合，导致IA亚区相对疏水的‘谷’发生‘铰链运动’。这一过程导致了蛋白的缓慢构象转变，使Co(II)的其他结合部位暴露出来，并显示出正的协同效应。Co(II)-HSA和Co(II)-BSA体系的LMCT(配体-金属电荷跃迁)带也表现出一种以偶极-偶极相互作用机制为特征的减色效应。这种现象很少有报道。
A notable hysteretic effect has been observed in the interaction of Co(II) with human serum albumin (HSA) or bovine serum albumin (BSA) using UV–Visible spectrometry at physiological pH (7.43), which shows that the binding between Co(II) and HSA or BSA may induce a slow transition of HSA or BSA from the conformation of weaker affinity for Co(II) to one of stronger affinity (A–B transition). The rate constants and activation parameters of this transition were measured and are discussed. It is inferred that such a conformation transition may occur due to the binding of the first Co(II) ion with the peptide segment of N-terminal residues 1–3, which results in a ‘hinged movement’ of the relatively hydrophobic ‘valley’ in the IA subdomain. This process leads to a slow conformational transition in the albumins, makes the other binding sites of Co(II) exposed, and shows a positive cooperativity effect. The LMCT (ligand-to-metal charge transition) bands of the Co(II)–HSA and Co(II)–BSA systems also show a kind of hypochromic effect featuring a dipole–dipole interaction mechanism. This phenomenon is rarely reported.