Structural and functional characterization of Dps-proteins-biomineralization versus DNA-protection

伊朗不仅是许多酶的重要辅助因子，也是细胞生命的主要威胁。尽管铁含量丰富，但铁的吸收受到损害，因为这种元素以不溶的形式存在äs Fe3+，而自由的Fe2*可以通过芬顿反应产生高活性的羟基自由基。在细菌和古细菌中，存在于细胞质中的胞内铁被Dps蛋白以一种生物可利用和无毒的形式储存在低聚壳中。然而，Dps蛋白具有第二种防御功能-通过蛋白质-DNA缩合来保护DNA。-我们最近通过x射线晶体学研究了Dps蛋白生物矿化的早期步骤。为了扩大我们目前对Dps家族蛋白生物矿化的看法，我们旨在通过各种生物物理方法研究真细菌和古细菌酶核心中隔离铁原子的精确数量和氧化态。将通过合成肽模拟成核和核形成，并研究Dps蛋白对不同性质离子（即Co+， Ni+, Hg+）的潜在摄取的可塑性。此外，我们希望在分子水平上分析Dps与DNA的相互作用，以及铁储存或DNA结合对Dps蛋白调控和稳定性的可能影响。

Iran is not only an essential cofactor of many enzymes but also a major threat to cellular life. Despite its abundance the uptake of iron is compromised, because this element occurs äs Fe3+ in a mostly insoluble form while free Fe2* can generate highly reactive hydroxyl radicals by Fenton reaction. In bacteria and archaea the intracellular iron present in the cytosol is incorporated by Dps proteins in a bioavailable and nontoxic form by storage into oligomeric Shells. However, Dps proteins carry out a second defense function - the DNA protection by protein-DNA condensation. - We have recently studied early steps of biomineralization in Dps proteins by X-ray crystallography. To expand our current view on biomineralization within Dps family proteins we aim to study i.e. the precise number and Oxidation states of sequestered iron atoms in the cores of eubacterial and archaeal enzymes by various biophysical methods. Nucleation and core formation will be mimicked by means of synthetic peptides and the plasticity of Dps proteins towards a potential uptake for ions of different nature will be studied (i.e. Co+, Ni+, Hg+). Furthermore we want to analyze the interactions between Dps and DNA at the molecular level and a possible influence of iron storage or DNA-binding onto regulation and stability of Dps proteins.