3MJO

Small subunit (R2F) of native ribonucleotide reductase from Corynebacterium ammoniagenes

Summary for 3MJO

• Entry DOI: 10.2210/pdb3mjo/pdb
• Descriptor: Ribonucleotide reductase subunit R2F, MANGANESE (III) ION (3 entities in total)
• Functional Keywords: mn ribonucleotide reductase, rnr, radical enzyme, split signal, metallocofactor, dna-precursor biosynthesis, oxidoreductase
• Biological source: Corynebacterium ammoniagenes (Brevibacterium ammoniagenes)
• Total number of polymer chains: 2
• Total formula weight: 68828.42

Authors

Ogata, H.,Stolle, P.,Stehr, M.,Auling, G.,Lubitz, W. (deposition date: 2010-04-13, release date: 2010-08-25, Last modification date: 2023-09-06)

Primary citation

Cox, N.,Ogata, H.,Stolle, P.,Reijerse, E.,Auling, G.,Lubitz, W.
A Tyrosyl-Dimanganese Coupled Spin System is the Native Metalloradical Cofactor of the R2F Subunit of the Ribonucleotide Reductase of Corynebacterium ammoniagenes.
J.Am.Chem.Soc., 132:11197-11213, 2010

PubMed Abstract: The X-ray crystallographic structure of the native R2F subunit of the ribonucleotide reductase (RNR) of Corynebacterium ammoniagenes ATCC 6872 is reported, with a resolution of 1.36 A. The metal site contains an oxo/hydroxo-bridged manganese dimer, located near a tyrosine residue (Y115). The coordination of the manganese dimer and its distance to a nearby tyrosine residue resemble the di-iron metalloradical cofactor of class I RNR from Escherichia coli . Multifrequency EPR measurements of the highly active C. ammoniagenes R2F subunit show that the metal site contains a ferromagnetically exchange-coupled Mn(III)Mn(III) dimer weakly coupled to a tyrosyl radical. A mechanism for the metalloradical cofactor (Mn(III)Mn(III)Y(*)) generation is proposed. H(2)O(2) (HO(2)(-)) instead of O(2) is hypothesized as physiological oxidant for the Mn dimer which in turn oxidizes the tyrosine Y115. Changes in the ligand sphere of both manganese ions during metalloradical generation direct the complex formation of this cofactor, disfavoring alternate reaction pathways such as H(2)O(2) dismutation, as observed for manganese catalase, a structural analogue of the R2F metal site. The presented results demonstrate the importance of manganese for radical formation in this RNR and confirm the assignment of this enzyme to class Ib.

PubMed: 20698687
DOI: 10.1021/ja1036995

Experimental method

X-RAY DIFFRACTION (1.36 Å)