Genome Property Definition Page

Nameclass I (aerobic) ribonucleotide reductase
DescriptionRibonucleotide reductases (RNRs) are responsible for the conversion of the ribose sugar of RNA into the deoxyribose sugar of DNA. This is the rate-limiting step of DNA biosynthesis. The class I RNRs [1] consist of two subunits, alpha and beta (also known as the large and small subunbits, respectively). Class I RNRs generate the required radical (on tyrosine) via a non-heme iron cofactor which resides in the beta subunit. The alpha subunit contains the catalytic and allosteric regulatory sites. The most common gene symbols for these genes are NrdE (alpha) and NrdF (beta), althought the first characterized complex from E.coli (NrdAB) turns out to be one of a pair in gammaproteobacteria and the more divergent one at that. Where multiple class I enzymes exist in a single organism they are presumed to be under differential regulation. Note that earlier reports of a manganese-based class IV system related to class I in high GC gram positive species was proved to be spurious [2]. Electrons for this reduction are supplied by glutaredoxin-like (NrdH, in some species [3]), or flavodoxins specific to this system which are in turn reduced by oxygen via thioredoxin reductase. Detection of this component is not required to set the YES state because of incomplete knowledge of the various homologs involved. Certain class I RNRs are associated with a gene of unknown function (NrdI). NrdI shows up more frequently, but not exclusively in species with more than one class I RNR, so it may be involved in regulation in some way.
JCVI Role2'-Deoxyribonucleotide metabolism
Parent PropertyGenProp0287: ribonucleotide reduction
Literature References
[ 1 ]Stubbe J  Di-iron-tyrosyl radical ribonucleotide reductases.  Curr Opin Chem Biol 2003 Apr;7(2):183-8.  PMID 12714050
[ 2 ]Hogbom M, Huque Y, Sjoberg BM, Nordlund P  Crystal structure of the di-iron/radical protein of ribonucleotide reductase from Corynebacterium ammoniagenes.  Biochemistry 2002 Jan 29;41(4):1381-9.  PMID 11802741
[ 3 ]Stehr M, Schneider G, Aslund F, Holmgren A, Lindqvist Y  Structural basis for the thioredoxin-like activity profile of the glutaredoxin-like NrdH-redoxin from Escherichia coli.  J Biol Chem 2001 Sep 21;276(38):35836-41. Epub 2001 Jul 5.  PMID 11441020
Gene Ontology TermGO:0009265: 2'-deoxyribonucleotide biosynthetic process (biological_process)

Step NameStep NumRequiredEvidence (Method)Evidence Go Terms
aerobic RNR, alpha (large) chainNrdA/EYESTIGR02506 (HMM): ribonucleoside-diphosphate reductase, alpha subunit
TIGR02510 (HMM): ribonucleoside-diphosphate reductase, alpha chain
GO:0009265: 2'-deoxyribonucleotide biosynthetic process
GO:0009265: 2'-deoxyribonucleotide biosynthetic process
aerobic RNR, beta (small) chainNrdB/FYESPF00268 (HMM): ribonucleoside-diphosphate reductase, beta subunitGO:0009265: 2'-deoxyribonucleotide biosynthetic process
Unknown functionNrdINOTIGR00333 (HMM): nrdI proteinGO:0009265: 2'-deoxyribonucleotide biosynthetic process
redoxin, ribonucleotide-reductase relatedredoxinNOTIGR02194 (HMM): glutaredoxin-like protein NrdH
TIGR01754 (HMM): putative ribonucleotide reductase-associated flavodoxin
GO:0009265: 2'-deoxyribonucleotide biosynthetic process
GO:0009265: 2'-deoxyribonucleotide biosynthetic process

Parent Properties
GenProp0287ribonucleotide reduction

Sibling Properties
GenProp0290class II (B12-dependent) ribonucleotide reductase
GenProp0291class III (anaerobic) ribonucleotide reductase