PROSITE documentation PDOC00317
Ribonucleotide reductase small subunit signature


Ribonucleotide reductase (EC [1,2] catalyzes the reductive synthesis of deoxyribonucleotides from their corresponding ribonucleotides. It provides the precursors necessary for DNA synthesis. Ribonucleotide reductase is an oligomeric enzyme composed of a large subunit (700 to 1000 residues) and a small subunit (300 to 400 residues).

The small chain binds two iron atoms [3] (three Glu, one Asp, and two His are involved in metal binding) and contains an active site tyrosine radical. The regions of the sequence that contain the metal-binding residues and the active site tyrosine are conserved in ribonucleotide reductase small chain from prokaryotes, eukaryotes and viruses.

We have selected one of these regions as a signature pattern. It contains the active site residue as well as a glutamate and a histidine involved in the binding of iron.

Last update:

December 2001 / Pattern and text revised.


Technical section

PROSITE method (with tools and information) covered by this documentation:

RIBORED_SMALL, PS00368; Ribonucleotide reductase small subunit signature  (PATTERN)


1AuthorsNillson O. Lundqvist T. Hahne S. Sjoberg B.-M.
SourceBiochem. Soc. Trans. 16:91-94(1988).

2AuthorsReichard P.
TitleFrom RNA to DNA, why so many ribonucleotide reductases?
SourceScience 260:1773-1777(1993).
PubMed ID8511586

3AuthorsNordlund P. Sjoberg B.-M. Eklund H.
TitleThree-dimensional structure of the free radical protein of ribonucleotide reductase.
SourceNature 345:593-598(1990).
PubMed ID2190093

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