An electrospray mass spectrometric study of organomercury(II) and mercuric interactions with peptides involving cysteinyl ligands
An electrospray mass spectrometric study of organomercury(II) and mercuric interactions with peptides involving cysteinyl ligands
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DOI：
10.1255/ejms.59
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发表时间：
1996-01-01
期刊：
影响因子：
--
通讯作者：
Canty, AJ
中科院分区：
文献类型：
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作者：
DAgostino, A;Colton, R;Canty, AJ
用正离子电喷雾质谱（MS）研究了Hg ~（2+）、[MeHg]（+）和[PhHg]（+）离子与半胱氨酸（Cys）、谷胱甘肽（GSH）和N端含一个半胱氨酰硫的多肽（Pp）的相互作用。MS/MS实验表明，有机汞的加合主要发生在巯基基团，与一些证据的异构体物种，其中有机汞阳离子结合到氨基或羧基基团，在谷胱甘肽和Pp的Ellman修改后，加合的有机汞阳离子的最大数量分别减少了2和1，表明[RHg]（+）和半胱氨酰硫之间的2：1和1：1的相互作用。与[PhHg]（+）不同，[MeHg]（+）对GSH和Pp中的半胱氨酰硫表现出几乎排他的亲和力。Cys和GSH均与Hg ~（2+）反应形成多核物种。[2Cys+Hg-H]（+）离子的碰撞活化质谱表明Hg（II）最有可能桥接在两个半胱氨酰残基之间，尽管不一定通过传统的-S-Hg-S-键。
Positive ion electrospray mass spectrometry (MS) has been used to investigate the interaction of Hg2+, [MeHg](+) and [PhHg](+) cations with cysteine (Cys), glutathione (GSH) and a 27-residue polypeptide (Pp) containing one cysteinyl sulfur located at the N-terminus. MS/MS experiments showed that organomercury adduction occurs primarily at the sulfhydryl group, with some evidence for isomeric species in which the organomercury cation is bound to either an amino or a carboxylic group, Following Ellman modification of GSH and Pp, the maximum number of adducted organomercury cations was reduced by 2 and 1, respectively, indicating a 2:1 and a 1:1 interaction between [RHg](+) and the cysteinyl sulfur. Unlike [PhHg](+), [MeHg](+) showed an almost exclusive affinity for the cysteinyl sulfur of GSH and Pp. Both Cys and GSH reacted with Hg2+ to form polynuclear species. Collisional activation mass spectra of the [2Cys+Hg-H](+) ion indicated that the Hg (II) was most probably bridged between the two cysteinyl residues, although not necessarily via a conventional -S-Hg-S-linkage.