1MRR

SUBSTITUTION OF MANGANESE FOR IRON IN RIBONUCLEOTIDE REDUCTASE FROM ESCHERICHIA COLI. SPECTROSCOPIC AND CRYSTALLOGRAPHIC CHARACTERIZATION

Summary for 1MRR

• Entry DOI: 10.2210/pdb1mrr/pdb
• Descriptor: RIBONUCLEOTIDE REDUCTASE R1 PROTEIN, MANGANESE (II) ION, MERCURY (II) ION, ... (4 entities in total)
• Functional Keywords: reductase(acting on ch2)
• Biological source: Escherichia coli
• Total number of polymer chains: 2
• Total formula weight: 89567.05

Authors

Eklund, H.,Nordlund, P. (deposition date: 1992-07-28, release date: 1994-01-31, Last modification date: 2024-10-30)

Primary citation

Atta, M.,Nordlund, P.,Aberg, A.,Eklund, H.,Fontecave, M.
Substitution of manganese for iron in ribonucleotide reductase from Escherichia coli. Spectroscopic and crystallographic characterization.
J.Biol.Chem., 267:20682-20688, 1992

PubMed Abstract: Each polypeptide chain of protein R2, the small subunit of ribonucleotide reductase from Escherichia coli, contains a stable tyrosyl radical and two antiferromagnetically coupled oxo-bridged ferric ions. A refined structure of R2 has been recently obtained. R2 can be converted into apoR2 by chelating out the metal cofactor and scavenging the radical. This study shows that apoR2 has a very strong affinity for four stable Mn2+ ions. The manganese-containing form of R2, named Mn-R2, has been studied by EPR spectroscopy and x-ray crystallography. It contains two binuclear manganese clusters in which the two manganese ions occupy the natural iron-binding sites and are only bridged by carboxylates from glutamates 115 and 238. This in turn explains why the spin-exchange interaction between the two ions is very weak and why Mn-R2 is EPR active. Mn-R2 could provide a model for the native diferrous form of protein R2, and a detailed molecular mechanism for the reduction of the iron center of protein R2 is proposed.

PubMed: 1328209

Experimental method

X-RAY DIFFRACTION (2.5 Å)