Evaluation of the association of mercury(II) with some dicysteinyl tripeptides.
Evaluation of the association of mercury(II) with some dicysteinyl tripeptides.
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DOI：
10.1016/j.bioorg.2012.06.001
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发表时间：
2012-10
影响因子：
5.1
通讯作者：
Ngu-Schwemlein M
中科院分区：
文献类型：
--
作者：
Lin X;Brooks J;Bronson M;Ngu-Schwemlein M
本研究旨在深入了解pH值为7.4的缓冲介质中汞（II）与二半胱氨酸三肽的关系。我们研究了增加半胱氨酸残基之间的距离对汞（II）结合和复合物形成的影响。采用等温滴定量热法测定了3-(N-morpholino)丙磺酸（MOPS）缓冲溶液中肽汞（II）的形成常数及其相关热力学参数。采用LTQ Orbitrap质谱法对甲酸铵缓冲溶液中不同相对比例的汞（II）与半胱氨酸肽形成的配合物进行了表征。这些研究结果表明，n-烷基二胱氨酸肽（CP 1-4）和芳基二胱氨酸肽（CP 5）可以作为有效的“双锚”来容纳汞（II）的配位位点，形成主要的一对一汞（肽）复合物。芳基二胱氨酸肽（cp5）也形成二对二Hg2（肽）2复合物。在多余肽存在的情况下，Hg（肽）2络合物也被检测到。值得注意的是，增加CP 1-5中连接基团或“锚点”之间的距离不会显著影响它们对汞（II）的亲和力。然而，CP 4和5与汞（II）形成络合物的焓变（ΔH）值（ΔH1 ~−91 kJ mol−1和ΔH2 ~−66 kJ mol−1）比CP 1、2和3的相关值（ΔH1 ~−66 kJ mol−1和ΔH2 ~−46 kJ mol−1）大1.5倍。结构较大的二半胱氨酸肽CP 4和5对应的熵变（ΔS）值（ΔS1 ~−129 J K−1 mol−1和ΔS2 ~−116 J K−1 mol−1）比CP 1、2和3 （ΔS1 ~−48 J K−1 mol−1和ΔS2 ~−44 J K−1 mol−1）的熵变（ΔS）值更不有利。通常，这些关联导致熵的减少，表明这些肽-汞复合物可能形成高度有序的结构。本研究结果表明，二半胱氨酸三肽能有效结合汞（II），它们是设计多半胱氨酸肽以结合多个汞（II）离子的有希望的基序。
The present study was undertaken to gain insight into the associations of mercury(II) with dicysteinyl tripeptides in buffered media at pH 7.4. We investigated the effects of increasing the distance between cysteinyl residues on mercury(II) associations and complex formations. The peptide–mercury(II) formation constants and their associated thermodynamic parameters in 3-(N-morpholino)propanesulfonic acid (MOPS) buffered solutions were evaluated by isothermal titration calorimetry. Complexes formed in different relative ratios of mercury(II) to cysteinyl peptides in ammonium formate buffered solutions were characterized by LTQ Orbitrap mass spectrometry. The results from these studies show that n-alkyl dicysteinyl peptides (CP 1–4), and an aryl dicysteinyl peptide (CP 5) can serve as effective “double anchors” to accommodate the coordination sites of mercury(II) to form predominantly one-to-one Hg(peptide) complexes. The aryl dicysteinyl peptide (CP 5) also forms the two-to-two Hg2(peptide)2 complex. In the presence of excess peptide, Hg(peptide)2 complexes are also detected. Notably, increasing the distance between the ligating groups or “anchor points” in CP 1–5 does not significantly affect their affinity for mercury(II). However, the enthalpy change (ΔH) values (ΔH1 ~ −91 kJ mol−1 and ΔH2 ~ −66 kJ mol−1) for complex formation between CP 4 and 5 with mercury(II) are about one and a half times larger than the related values for CP 1, 2 and 3 (ΔH1 ~ −66 kJ mol−1 and ΔH2 ~ −46 kJ mol−1). The corresponding entropy change (ΔS) values (ΔS1 ~ −129 J K−1 mol−1 and ΔS2 ~ −116 J K−1 mol−1) of the structurally larger dicysteinyl peptides CP 4 and 5 are less entropically favorable than for CP 1, 2 and 3 (ΔS1 ~ −48 J K−1 mol−1 and ΔS2 ~ −44 J K−1 mol−1). Generally, these associations result in a decrease in entropy, indicating that these peptide–mercury complexes potentially form highly ordered structures. The results from this study show that dicysteinyl tripeptides are effective in binding mercury(II) and they are promising motifs for the design of multi-cysteinyl peptides for binding more than one mercury(II) ion per peptide.
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影响因子：
4.3
作者：
Krupp, Eva M.;Milne, Bruce F.;Mestrot, Adrien;Meharg, Andrew A.;Feldmann, Jorg
通讯作者：
Feldmann, Jorg
影响因子：
3.9
作者：
CHURCH, HJ;DAY, JP;BROWN, SS
通讯作者：
BROWN, SS
影响因子：
3.5
作者：
Ngu-Schwemlein, Maria;Gilbert, Willie;Schwemlein, Stefanie
通讯作者：
Schwemlein, Stefanie
影响因子：
4.5
作者：
APOSHIAN, HV;MAIORINO, RM;APOSHIAN, MM
通讯作者：
APOSHIAN, MM
影响因子：
11.4
作者：
Chekmeneva, Elena;Manuel Diaz-Cruz, Jose;Esteban, Miquel
通讯作者：
Esteban, Miquel