Ether cross-link formation in the R2-like ligand-binding oxidase.

Griese JJ, Branca RMM, Srinivas V, Högbom M

J. Biol. Inorg. Chem. 23 (6) 879-886 [2018-08-00; online 2018-06-26]

R2-like ligand-binding oxidases contain a dinuclear metal cofactor which can consist either of two iron ions or one manganese and one iron ion, but the heterodinuclear Mn/Fe cofactor is the preferred assembly in the presence of Mn II and FeII in vitro. We have previously shown that both types of cofactor are capable of catalyzing formation of a tyrosine-valine ether cross-link in the protein scaffold. Here we demonstrate that Mn/Fe centers catalyze cross-link formation more efficiently than Fe/Fe centers, indicating that the heterodinuclear cofactor is the biologically relevant one. We further explore the chemical potential of the Mn/Fe cofactor by introducing mutations at the cross-linking valine residue. We find that cross-link formation is possible also to the tertiary beta-carbon in an isoleucine, but not to the secondary beta-carbon or tertiary gamma-carbon in a leucine, nor to the primary beta-carbon of an alanine. These results illustrate that the reactivity of the cofactor is highly specific and directed.

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PubMed 29946980

DOI 10.1007/s00775-018-1583-3

Crossref 10.1007/s00775-018-1583-3

10.1007/s00775-018-1583-3

pmc PMC6060897