Insight into the preferential N-bindingversusO-binding of nitrosoarenes to ferrous and ferric heme centers

Erwin G. Abucayon, Jia Min Chu, Megan Ayala, Rahul L. Khade, Yong Zhang, George B. Richter-Addo

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Nitrosoarenes (ArNOs) are toxic metabolic intermediates that bind to heme proteins to inhibit their functions. Although much of their biological functions involve coordination to the Fe centers of hemes, the factors that determine N-binding or O-binding of these ArNOs have not been determined. We utilize X-ray crystallography and density functional theory (DFT) analyses of new representative ferrous and ferric ArNO compounds to provide the first theoretical insight into preferential N-bindingversusO-binding of ArNOs to hemes. Our X-ray structural results favored N-binding of ArNO to ferrous heme centers, and O-binding to ferric hemes. Results of the DFT calculations rationalize this preferential binding on the basis of the energies of associated spin-states, and reveal that the dominant stabilization forces in the observed ferrous N-coordination and ferric O-coordination are dπ-pπ* and dσ-pπ*, respectively. Our results provide, for the first time, an explanation whyin situoxidation of the ferrous-ArNO compound to its ferric state results in the observed subsequent dissociation of the ligand.

Original languageEnglish
Pages (from-to)3487-3498
Number of pages12
JournalDalton Transactions
Volume50
Issue number10
DOIs
StatePublished - 14 Mar 2021

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