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

• Applicant: Professor Dr. Kornelius Zeth
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2006 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 28381897

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.

• DFG Programme: Research Grants