亚砷酸盐与锌指 CCHC 肽的相互作用：形成 As-Zn-肽混合配合物的证据。
Interaction of arsenite with a zinc finger CCHC peptide: evidence for formation of an As-Zn-peptide mixed complex.
机构信息
Departamento de Química, Instituto de Ciências Exatas, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Pampulha, Belo Horizonte, MG, Brazil.
出版信息
J Inorg Biochem. 2011 Dec;105(12):1753-8. doi: 10.1016/j.jinorgbio.2011.09.023. Epub 2011 Sep 22.
The interaction of arsenite with a Cys(3)His (CCHC) zinc finger model (34-51) HIV-1 nucleocapsid protein p7 (NCp7) peptide in the absence and presence of Zn(II) was studied using fluorescence spectroscopy, CD (circular dichroism) and ESI-MS (Electrospray Ionization Mass Spectrometry). We found that arsenic forms different complexes with the free peptide and the zinc finger peptide. In the former case the peptide conformation differed greatly from that of the zinc finger, whereas in the second case a mixed As-Zn-peptide complex was formed with partial preservation of zinc finger conformation. An apparent stability constant was estimated for the mixed As-Zn-peptide complex (K=2083 M(-1) and 442 M(-1) at 25°C and pHs 6 and 7, respectively). Our study also shows that the interaction of arsenic with the CCHC motif is facilitated by glutathione (GSH), through formation of a GS-As-peptide conjugate.
使用荧光光谱法、圆二色性（CD）和电喷雾电离质谱（ESI-MS）研究了亚砷酸盐与 Cys(3)His (CCHC) 锌指模型（34-51）HIV-1 核衣壳蛋白 p7 (NCp7) 肽在无锌和有锌条件下的相互作用。我们发现砷与游离肽和锌指肽形成不同的配合物。在前一种情况下，肽构象与锌指有很大差异，而在后一种情况下，形成了部分保留锌指构象的混合 As-Zn-肽配合物。分别在 25°C 和 pH 值为 6 和 7 时，估算了混合 As-Zn-肽配合物的表观稳定常数（K=2083 M(-1) 和 442 M(-1)）。我们的研究还表明，谷胱甘肽（GSH）通过形成 GS-As-肽缀合物，促进了砷与 CCHC 基序的相互作用。
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