Spectroscopy and DFT Calculations of Flavo-Diiron Nitric Oxide Reductase Identify Bridging Structures of NO-Coordinated Diiron Intermediates.

ABSTRACT: Flavo-diiron proteins (FDPs) are widespread in anaerobic bacteria, archaea, and protozoa, where they serve as the terminal components of dioxygen and nitric oxide reductive scavenging pathways. FDPs contain an N,O-ligated diiron site adjacent to a flavin mononucleotide (FMN) cofactor. The diiron site is structurally similar to those in hemerythrin, ribonucleotide reductase, and methane monooxygenase. However, only FDPs turn over NO to N2O at significant rates and yields. Previous studies revealed sequential binding of two NO molecules to the diferrous site, forming mono- and dinitrosyl intermediates leading to N2O formation. In the present work, these mono- and dinitrosyl intermediates have been characterized by EPR and Mössbauer spectroscopies and DFT calculations. Our results show that t

SUBMITTER: Weitz AC 

PROVIDER: S-EPMC6602092 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature