Ternary Cu(II) complexes, Cu(H(-1)L)(ACys-) and Cu(H(-2)L)(ACys-); L = peptides, ACys- = N-acetyl-cysteinate. Analogous complexes to the intermediates in the transport of Cu(II) from Cu(H(-2)L) to cysteine.
Ternary Cu(II) complexes, Cu(H(-1)L)(ACys-) and Cu(H(-2)L)(ACys-); L = peptides, ACys- = N-acetyl-cysteinate. Analogous complexes to the intermediates in the transport of Cu(II) from Cu(H(-2)L) to cysteine.
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DOI：
10.1016/j.jinorgbio.2005.11.017
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发表时间：
2006-03
影响因子：
3.9
通讯作者：
A. Hanaki;Y. Funahashi;A. Odani
中科院分区：
文献类型：
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作者：
A. Hanaki;Y. Funahashi;A. Odani
Cu（H−2L）中的Cu（II）被假定为依次转运到半胱氨酸（Cys）中：Cu（H − 2L）<$Cu（H − 2L）（Cys <$−）<$Cu（H− 1 L）（Cys <$−）→Cu（H − 1 L）（Cys−），其中Cys <$−表示单齿Cys−。N-乙酰基-半胱氨酸（ACys−）配合物Cu（H−2L）（ACys−）和Cu（H− 1 L）（ACys−）分别具有与Cu（H−2L）（Cys <$−）和Cu（H− 1 L）（Cys <$−）相似的配位模式，在325- 355 nm处具有S→Cu（II）电荷转移吸收，在530- 610 nm处具有d-d吸收。CD能级与d能级之间存在线性关系。Cu（H−2L）（ACys−）与Cu（H− 1 L）（ACys−）快速平衡。在形成三元配合物时，母体Cu（H− 1 L）的pKc 2升高到1.0以上。由Cu（H − 1 L）生成Cu（H − 1 L）（ACys−）物种的生成常数（K）大于由Cu（H − 2L）生成Cu（H − 2L）（ACys−）物种的生成常数（K）。三元络合物形成过程中的自由能变化（ΔG）与熵变（ΔS）之间存在线性关系。Cu（H− 1 L）（Cys−）形成的速率常数（k1+）与Cu（H−2L）（ACys−）的K值密切相关。含有ACys的三元配合物被认为是类似的配合物的中间体中的铜（II）从肽半胱氨酸的运输。
The Cu(II) in Cu(H−2L) has been postulated to be successively transported to cysteine (Cys) as follows; Cu(H−2L)⇄Cu(H−2L)(Cys∗−)⇄Cu(H−1L)(Cys∗−)→Cu(H−1L)(Cys−), where Cys∗−denotes the monodentate Cys−. N-acetyl-cysteinate (ACys−) complexes Cu(H−2L)(ACys−) and Cu(H−1L)(ACys−), having similar coordination modes to Cu(H−2L)(Cys∗−) and Cu(H−1L)(Cys∗−), respectively, exhibited the S→Cu(II) charge transfer absorption at 325–355nm and the d–d absorption at 530–610nm. A linear interrelation existed between the energies of the CD and d–d absorptions. Cu(H−2L)(ACys−) were in rapid equilibrium with Cu(H−1L)(ACys−). Upon forming the ternary complex, pKc2of the parent Cu(H−1L) was raised to more than 1.0. The formation constants (K) of the Cu(H−1L)(ACys−) species from Cu(H−1L) were bigger than those of Cu(H−2L)(ACys−) from Cu(H−2L). The linear free-energy relationship existed between the free-energy change (ΔG) and the entropy change (ΔS) for the ternary complex formation. The rate constants (k1+) for the Cu(H−1L)(Cys−) formation closely correlated with the K values for Cu(H−2L)(ACys−). The ternary complexes containing ACys are considered to be analogous complexes to the intermediates in the transport of Cu(II) from peptides to cysteine.