The Electronic Structure of the Metal Active Site Determines the Geometric Structure and Function of the Metalloregulator NikR

Journal Article · Wed Jul 24 00:00:00 EDT 2019 · Biochemistry

DOI:https://doi.org/10.1021/acs.biochem.9b00542· OSTI ID:1562487

Ha, Yang ^[1]; Hu, Heidi ^[2]; Higgins, Khadine ^[2]; Maroney, Michael ^[2]; Hedman, Britt ^[3]; Hodgson, Keith ^[1]; Solomon, Edward ^[1]

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1. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
2. Univ. of Massachusetts Amherst, Amherst, MA (United States)
3. SLAC National Accelerator Lab., Menlo Park, CA (United States)

NikR 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 Z_eff 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. Furthermore, this contribution of electronic structure to geometric structure can be extended to other metal selective metalloregulators.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC02-76SF00515
• OSTI ID: 1562487
• Journal Information: Biochemistry, Journal Name: Biochemistry Journal Issue: 34 Vol. 58; ISSN 0006-2960
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY