¹³C ENDOR Characterization of the Central Carbon within the Nitrogenase Catalytic Cofactor Indicates That the CFe₆ Core Is a Stabilizing "Heart of Steel".

ABSTRACT: Substrates and inhibitors of Mo-dependent nitrogenase bind and react at Fe ions of the active-site FeMo-cofactor [7Fe-9S-C-Mo-homocitrate] contained within the MoFe protein α-subunit. The cofactor contains a CFe₆ core, a carbon centered within a trigonal prism of six Fe, whose role in catalysis is unknown. Targeted ¹³C labeling of the carbon enables electron-nuclear double resonance (ENDOR) spectroscopy to sensitively monitor the electronic properties of the Fe-C bonds and the spin-coupling scheme adopted by the FeMo-cofactor metal ions. This report compares ¹³CFe₆ ENDOR measurements for (i) the wild-type protein resting state (E₀; α-Val⁷⁰) to those of (ii) α-Ile⁷⁰, (iii) α-Ala⁷⁰-substituted prot

SUBMITTER: Lukoyanov DA 

PROVIDER: S-EPMC10712652 | biostudies-literature | 2022 Oct

REPOSITORIES: biostudies-literature