Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, 50-383 Wroclaw, Poland.
Dalton Trans. 2017 Oct 17;46(40):13695-13703. doi: 10.1039/c7dt01675a.
The aim of this work is to understand the interactions of Zn(ii) with Pra1, a zincophore from Candida albicans, one of the most common causes of serious fungal infections in humans. Pra1 is a 299 amino acid protein, secreted from the fungus to specifically bind Zn(ii) and deliver it to a transmembrane zinc transporter, Zrt1. We take the first step towards understanding the bioinorganic chemistry of this process, by pointing out the Zn(ii) binding sites in Pra1 and understanding the thermodynamics of such interactions. Our approach involves working on model systems (unstructured parts of proteins) in order to identify those regions in Pra1, to which zinc binds with the highest affinity. Mass spectrometry shows the stoichiometry of Zn(ii)-peptide complex formation and potentiometric studies give us the partial and overall stability constants for all the formed zinc complexes. NMR clarifies binding sites in the case of doubts. A detailed comparison of these results shows that the C-terminal region of Pra1 binds Zn(ii) with the highest affinity, indicating that this region of the zincophore is responsible for the binding of zinc. Such knowledge is an input to the basic bioinorganic chemistry of zinc; it allows us to understand the inorganic biochemistry of zincophores, and it might be a stepping stone towards finding new, fungus specific treatments based on parts of zincophores coupled with antifungal drugs.
这项工作的目的是了解 Zn(ii)与 Pra1 的相互作用，Pra1 是一种来自白色念珠菌的锌载体，白色念珠菌是人类最常见的严重真菌感染的原因之一。Pra1 是一种 299 个氨基酸的蛋白质，从真菌中分泌出来，专门与 Zn(ii)结合，并将其递送到跨膜锌转运体 Zrt1。我们通过指出 Pra1 中的 Zn(ii)结合位点并了解这种相互作用的热力学，朝着理解这个生物无机化学过程迈出了第一步。我们的方法涉及研究模型系统（蛋白质的无结构部分），以确定 Pra1 中与锌结合亲和力最高的区域。质谱显示 Zn(ii)-肽复合物形成的化学计量比，而电位研究为所有形成的锌配合物提供了部分和整体稳定常数。在有疑问的情况下，NMR 澄清了结合位点。对这些结果的详细比较表明，Pra1 的 C 末端区域与 Zn(ii)结合的亲和力最高，表明锌载体的这一区域负责锌的结合。这种知识是锌的基础生物无机化学的输入；它使我们能够理解锌载体的无机生物化学，并且可能是基于锌载体与抗真菌药物结合的寻找新的、针对真菌的治疗方法的垫脚石。
