Wydział Chemii

Magdalena Rowińska-Żyrek

2017

Inorganica Chimica Acta

460

141-147

10.1016/j.ica.2016.08.007

Naukowa

Angielski

Artykuł

Nickel ions are the key element of metabolism in numerous lower organisms. They are required for the activity of nine enzymes, e.g. [NiFe] hydrogenase, which catalyzes the reversible oxidation of molecular hydrogen for energy production. Nickel homeostasis and nickel transport into the cell are strictly controlled.

HupE is a transmembrane nickel transporter in Rhizobium leguminosarum hydrogenase system which has a conserved, periplasmic, N-terminal domain responsible for nickel binding. This work focuses on the interactions of this region with native Ni²⁺ and two other metal ions (Cu²⁺ and Zn²⁺), which might interfere with nickel binding to the HupE fragment. Metal coordination sites are assigned and thermodynamic parameters are discussed in detail in order to evaluate the potential effectiveness of different soil concentrations of Cu²⁺ and Zn²⁺ to displace Ni²⁺ from its binding site.

At physiological pH, the coordination sphere of all three metal complexes consists of the imidazole and amine nitrogens of His1 (a histamine-like binding) and of the imidazole of His5. Cu²⁺ is able to displace Ni²⁺ from its binding site, while Zn²⁺ cannot, neither at equimolar concentrations, nor at soil metal concentrations at which Rhizobium leguminosarum numbers are expected to decrease by several orders of magnitude.

Metal-peptide complexes, thermodynamic stability, HupE nickel transporter

http://dx.doi.org/10.1016/10.1016/j.ica.2016.08.007

http://www.elsevier.com