A Mycobacterium tuberculosis ligand-binding Mn/Fe protein reveals a new cofactor in a remodeled R2-protein scaffold

• Chlamydia trachomatis R2c is the prototype for a recently discovered group of ribonucleotide reductase R2 proteins that use a heterodinuclear Mn/Fe redox cofactor for radical generation and storage. Here, we show that the Mycobacterium tuberculosis protein Rv0233, an R2 homologue and a potential virulence factor, contains the heterodinuclear manganese/iron-carboxylate cofactor but displays a drastic remodeling of the R2 protein scaffold into a ligand-binding oxidase. The first structural characterization of the heterodinuclear cofactor shows that the site is highly specific for manganese and iron in their respective positions despite a symmetric arrangement of coordinating residues. In this protein scaffold, the Mn/Fe cofactor supports potent 2-electron oxidations as revealed by an unprecedented tyrosine-valine crosslink in the active site. This wolf in sheep's clothing defines a distinct functional group among R2 homologues and may represent a structural and functional counterpart of the evolutionary ancestor of R2s and bacterial multicomponent monooxygenases.

Ämnesord

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Nyckelord

bioinorganic chemistry

diiron

manganese

monooxygenase

R2c

NATURAL SCIENCES

NATURVETENSKAP

Biophysics

biofysik

Biochemistry

biokemi

Biology

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ref (ämneskategori)

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