Wydział Chemii

Aleksandra Hecel

Arian Kola

Daniela Valensin

Henryk Kozłowski

Magdalena Rowińska-Żyrek

2020

Inorganic Chemistry

59

1947-1958

10.1021/acs.inorgchem.9b03298

Naukowa

Angielski

Artykuł

The crystal structure of ZnZnuA from Escherichia coli reveals two metal binding sites. (i) The primary binding site, His143, is located close the His-rich loop (residues 116–138) and plays a significant role in Zn(II) acquisition. (ii) The secondary binding site involves His224. In this work, we focus on understanding the interactions of two metal ions, Zn(II) and Cu(II), with two regions of ZnuA, which are possible anchoring sites for Zn(II): Ac-₁₁₅MKSIHGDDDDHDHAEKSDEDHHHGDFNMHLW₁₄₅-NH₂ (primary metal binding site) and Ac-₂₂₃GHFTVNPEIQPGAQRLHE₂₄₀-NH₂ (secondary metal binding site). The histidine-rich loop (residues 116–138) has a role in the capture of zinc(II), which is then further delivered into other regions of the protein. For both Zn(II) complexes, histidine residues constitute the main anchoring donors. In the longer, His-rich fragment, a tetrahedral complex with four His residues is formed, while in the second ligand, two imidazole nitrogens are involved in zinc(II) binding. In both cases, so-called loop structures are formed. One consists of a ₁₂₅HxHxExxxExHxH₁₃₇ motif with seven amino acid residues in the loop between the two central histidines, while the other is formed by a ₂₂₄HFTVNPEIQPGAQRLH₂₃₉ motif with 14 amino acid residues in the loop between the two nearest coordinating histidines. The number of available imidazoles also strongly affects the structure of copper(II) complexes; the more histidines in the studied region, the higher the pH in which amide nitrogens will participate in Cu(II) binding.

Peptides and proteins, Metals, Ligands, Monomers, Ions

CC-BY

http://dx.doi.org/10.1021/acs.inorgchem.9b03298

https://www.acs.org/content/acs/en.html