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ribonucleotide reductase B2 subunit (M2 subunit, ribonucleotide reductase small subunit, RRM2, RR2)
Function:
- provides precursors for DNA synthesis
- catalyzes the biosynthesis of deoxyribonucleotides from the corresponding ribonucleotides
- heterodimer of a large (M1) & a small chain (M2)
- DNA replication
- 2 distinct regulatory sites have been defined:
a) specificity site, which controls substrate specificity
b) activity site which regulates overall catalytic activity
- substrate-binding catalytic site, located on M1, is formed only in the presence of the second subunit M2
2'-deoxyribonucleoside diphosphate + thioredoxin disulfide + H2O
ribonucleoside diphosphate + thioredoxin
Cofactor: binds 2 Fe+2/Fe+3 per subunit (putative)
Structure:
- belongs to the ribonucleoside diphosphate reductase small chain family
Compartment: cytoplasm
Pathology:
- ribonucleotide reductase is thought to mediate pathogenesis of the immunodeficiency of
a) adenosine deaminase deficiency
b) purine nucleoside phosphorylase deficiency
- deoxynucleotides that accumulate in lymphoid cells are thought to feed-back inhibit ribonucleotide reductase, preventing DNA replication & cell proliferation
General
oligomerizing protein
protein subunit
Properties
SIZE: entity length = 389 aa
MW = 45 kD
MOTIF: Ser phosphorylation site {S20}
Iron [Fe]-binding site
SITE: 138-138
Iron [Fe]-binding site
SITE: 169-169
Iron [Fe]-binding site
SITE: 172-172
tyrosine residue {Y176}
Iron [Fe]-binding site
SITE: 232-232
Iron [Fe]-binding site
SITE: 266-266
Iron [Fe]-binding site
SITE: 269-269
Database Correlations
OMIM 180390
UniProt P31350
Pfam PF00268
ENZYME 1.17.4.1
References
- Stryer Biochemistry WH Freeman & Co, New York,
1988 pg 610
- UniProt :accession P31350
- Wikipedia; ribonucleotide reductase entry
http://en.wikipedia.org/wiki/ribonucleotide_reductase
Component-of
ribonucleotide diphosphate reductase