EPR-Derived Structure of a Paramagnetic Intermediate Generated by Biotin Synthase BioB.

ABSTRACT: Biotin (vitamin B₇) is an enzyme cofactor required by organisms from all branches of life but synthesized only in microbes and plants. In the final step of biotin biosynthesis, a radical S-adenosyl-l-methionine (SAM) enzyme, biotin synthase (BioB), converts the substrate dethiobiotin to biotin through the stepwise formation of two C-S bonds. Previous electron paramagnetic resonance (EPR) spectroscopic studies identified a semistable intermediate in the formation of the first C-S bond as 9-mercaptodethiobiotin linked to a paramagnetic [2Fe-2S] cluster through one of its bridging sulfides. Herein, we report orientation-selected pulse EPR spectroscopic results that reveal hyperfine interactions between the [2Fe-2S] cluster and a number of magnetic nuclei (e.g., ⁵⁷Fe,

SUBMITTER: Tao L 

PROVIDER: S-EPMC6363123 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature