{PDOC00317} {PS00368; RIBORED_SMALL} {BEGIN} **************************************************** * Ribonucleotide reductase small subunit signature * **************************************************** Ribonucleotide reductase (EC 1.17.4.1) [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. -Consensus pattern: [IVMSEQ]-E-x(1,2)-[LIVTA]-[HY]-[GSA]-x-[STAVM]-Y-x(2)- [LIVMQ]-x(3)-[LIVFY]-[IVFYCSA] [E and H bind iron, Y is the active site residue] -Sequences known to belong to this class detected by the pattern: ALL. -Other sequence(s) detected in Swiss-Prot: NONE. -Last update: December 2001 / Pattern and text revised. [ 1] Nillson O., Lundqvist T., Hahne S., Sjoberg B.-M. Biochem. Soc. Trans. 16:91-94(1988). [ 2] Reichard P. "From RNA to DNA, why so many ribonucleotide reductases?" Science 260:1773-1777(1993). PubMed=8511586 [ 3] Nordlund P., Sjoberg B.-M., Eklund H. "Three-dimensional structure of the free radical protein of ribonucleotide reductase." Nature 345:593-598(1990). PubMed=2190093; DOI=10.1038/345593a0 -------------------------------------------------------------------------------- PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND 4.0) License, see https://prosite.expasy.org/prosite_license.html -------------------------------------------------------------------------------- {END}