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The Electronic Structure of the Metal Active Site Determines the Geometric Structure and Function of the Metalloregulator NikR
journal contribution
posted on 2019-08-14, 13:39 authored by Yang Ha, Heidi Hu, Khadine Higgins, Michael Maroney, Britt Hedman, Keith Hodgson, Edward SolomonNikR
is a nickel-responsive metalloregulator protein that controls
the level of Ni2+ ions in living cells. Previous studies
have shown that NikR can bind a series of first-row transition metal
ions but binds to DNA with high affinity only as a Ni2+ complex. To understand this metal selectivity, S K-edge X-ray absorption
spectroscopy of NikR bound to different metal ions was used to evaluate
the different electronic structures. The experimental results are
coupled with density functional theory calculations on relevant models.
This study shows that both the Zeff of
the metal ion and the donor nature of the ligands determine the electronic
structure of the metal site. This impacts the geometric structure
of the metal site and thus the conformation of the protein. This contribution
of electronic structure to geometric structure can be extended to
other metal selective metalloregulators.