Allen M H, Hutchens T W
Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030.
Rapid Commun Mass Spectrom. 1992 Apr;6(4):308-12. doi: 10.1002/rcm.1290060418.
Conditions have been developed to characterize the reversible interaction of one or more Zn(II) ions with cysteine (sulfur) ligands on metal-binding peptides by electrospray-ionization (ES) mass spectrometry. A 71-residue peptide with two separate clusters of four cysteine residues was selected as a model to optimize both the solution and electrospray variables most likely to affect the detection of stable cysteine (sulfur) ligand/Zn interactions. By infusing peptide in water alone, stable electrospray and ion signals were produced in both the absence and presence of up to 100 microM zinc sulfate. In the absence of Zn(II), the calculated mass of the fully reduced peptide (8248.5 Da) was observed (8248.4 +/- 0.4 Da). In the presence of Zn(II), peptides with zero, one and two bound Zn atoms were detected; all three species were present in several different charge states. The overall charge envelope was typically unchanged in the presence of Zn; the charge-state optimum (10+) observed for this peptide was apparently unaffected by the presence of bound Zn. The interaction of Zn(II) ions with sulfur ligands in this peptide appeared to result in tetracoordinate covalent bonds.(ABSTRACT TRUNCATED AT 250 WORDS)
已经开发出相关条件，通过电喷雾电离（ES）质谱法来表征一个或多个锌离子（Zn(II)）与金属结合肽上的半胱氨酸（硫）配体之间的可逆相互作用。选择了一种含有两个由四个半胱氨酸残基组成的独立簇的71个残基的肽作为模型，以优化最有可能影响稳定的半胱氨酸（硫）配体/锌相互作用检测的溶液和电喷雾变量。仅通过将肽注入水中，在不存在和存在高达100微摩尔硫酸锌的情况下都产生了稳定的电喷雾和离子信号。在不存在Zn(II)的情况下，观察到完全还原肽的计算质量（8248.5道尔顿）（8248.4±0.4道尔顿）。在存在Zn(II)的情况下，检测到结合了零个、一个和两个锌原子的肽；所有这三种物种都以几种不同的电荷状态存在。在存在锌的情况下，总体电荷包络通常不变；该肽观察到的最佳电荷状态（10+）显然不受结合锌的存在的影响。该肽中Zn(II)离子与硫配体的相互作用似乎导致了四配位共价键。（摘要截短至250字）
