Pneumococcal histidine triads – involved not only in Zn2+, but also Ni2+binding?

February 28, 2019

Title

Pneumococcal histidine triads – involved not only in Zn2+, but also Ni2+binding?

Author

Adriana Miller, Dorota Loboda, Slawomir Potocki, Hanna Czapor-Irzabek, Henryk Kozlowski, Magdalena Rowinska-Zyrek

Year

2018

Journal

Metallomics

Abstract

Polyhistidine triad proteins, which participate in Zn2+ uptake in Streptococcus pneumoniae, contain multiple copies of the HxxHxH (histidine triad motif) sequence. We focus on three such motifs from one of the most common and well-conserved polyhistidine triad proteins, PhtA, in order to understand their bioinorganic chemistry; particular focus is given to (i) understanding which of the PhtA triads binds Zn2+ with the highest affinity (and why?) and (ii) explaining if Ni2+ (also crucial for bacterial survival and virulence) could potentially outcompete Zn2+ from its native binding site. There is no significant difference in the stability of zinc(II) complexes with the three studied protein fragments, but one of the nickel(II)-polyhistidine triad is remarkably stable; we explain why and hypothesize about the biological importance of this finding.

Instrument

J-1500

Keywords

Circular dichroism, Coordination chemistry, Chemical stability, Inorganic chemistry