Development of Nonheme {FeNO}⁷ Complexes Based on the Pyrococcus furiosus Rubredoxin for Red-Light-Controllable Nitric Oxide Release

Abstract

Nitric oxide (NO) is an essential biological messenger, contributing a significant role in a diverse range of physiological processes. The light-controllable NO releasers are of great interest because of their potential as agents for NO-related research and therapeutics. Herein, we developed a pair of red-light-controllable NO releasers, pfRd-C9A-{FeNO}7 and pfRd-C42A-{FeNO}7 (pfRd = Pyrococcus furiosus rubredoxin), by constructing a nonheme {FeNO}7 center within the redesigned iron–sulfur protein scaffolds. While shown to be both air and thermally stable, these complexes are highly sensitive to red-light irradiation with temporal precision, which was confirmed by electron paramagnetic resonance spin trapping and Griess assay. The temporally controlled NO release from these complexes was also demonstrated in DNA cleavage assay. Overall, this study demonstrates that such a protein-based nonheme iron nitrosyl system could be a viable chemical tool for precise NO administration.

Designing Artificial Metalloenzymes by Tuning of the Environment beyond the Primary Coordination Sphere

“…278 Using this approach, Lin and He were able to generate an open binding site for Fe III in Rd from Pyrococcus f uriosus (Pf) and subsequently bind NO following reduction with sodium dithionite (DT) to form an airstable C9A {FeNO} 7 -Rb (and equivalently C41A {FeNO} 7 -Rb). 272 The dominant S = 3/2 species was characterized by EPR and absorption spectroscopies; interestingly, an additional S = 1/2 signal was also observed and assigned to a nonspecifically bound {FeNO} 7 species. Irradiation with red light (625−650 nm) resulted in the stoichiometric release of NO from both C8A {FeNO} 7 -Rb and C41A {FeNO} 7 -Rb systems under either aerobic or anaerobic conditions.…”

“…(c) Cu-bound metal binding site of M121H/H46GE (PDB ID: 4WKX). PCS atoms are highlighted in light gray, while SCS target residues are highlighted in blue. Atom coloring: S (yellow); O (red); N (blue); Fe (orange); Cu (copper).…”

“…Substituting either Cys8 or Cys41 for Ala in Clostridium pasteurianum ( Cp ) Rd it has been shown to open a binding site, forming Fe­(Cys) 3 (OH) coordination . Using this approach, Lin and He were able to generate an open binding site for Fe III in Rd from Pyrococcus furiosus ( Pf ) and subsequently bind NO following reduction with sodium dithionite (DT) to form an air-stable C9A {FeNO} 7 -Rb (and equivalently C41A {FeNO} 7 -Rb) . The dominant S = 3/2 species was characterized by EPR and absorption spectroscopies; interestingly, an additional S = 1/2 signal was also observed and assigned to a nonspecifically bound {FeNO} 7 species.…”