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CATH Superfamily 1.10.620.20

Ribonucleotide Reductase, subunit A

The name of this superfamily has been modified since the most recent official CATH+ release (v4_2_0). At the point of the last release, this superfamily was named:

"
Ribonucleotide Reductase, subunit A
".

Functional Families

Overview of the Structural Clusters (SC) and Functional Families within this CATH Superfamily. Clusters with a representative structure are represented by a filled circle.
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FunFam 3351: Ribonucleoside-diphosphate reductase small chain

There are 1 EC terms in this cluster

Please note: EC annotations are assigned to the full protein sequence rather than individual protein domains. Since a given protein can contain multiple domains, it is possible that some of the annotations below come from additional domains that occur in the same protein, but have been classified elsewhere in CATH.

Note: The search results have been sorted with the annotations that are found most frequently at the top of the list. The results can be filtered by typing text into the search box at the top of the table.

EC Term Annotations Evidence
Ribonucleoside-diphosphate reductase. [EC: 1.17.4.1]
2'-deoxyribonucleoside diphosphate + thioredoxin disulfide + H(2)O = ribonucleoside diphosphate + thioredoxin.
  • This enzyme is responsible for the de novo conversion of ribonucleoside diphosphates into deoxyribonucleoside diphosphates, which are essential for DNA synthesis and repair.
  • There are three types of this enzyme differing in their cofactors.
  • Class Ia enzymes contain a diferric-tyrosyl radical, class Ib enzymes contain a dimanganese-tyrosyl radical, and class II enzymes contain adenosylcobalamin.
  • In all cases the cofactors are involved in generation of a transient thiyl radical on a cysteine residue, which attacks the substrate, forming a ribonucleotide 3'-radical, followed by water loss to form a ketyl radical.
  • The ketyl radical is reduced to 3'-keto-deoxynucleotide concomitant with formation of a disulfide anion radical between two cysteine residues.
  • A proton-coupled electron-transfer from the disulfide radical to the substrate generates a 3'-deoxynucleotide radical, and the the final product is formed when the hydrogen atom that was initially removed from the 3'-position of the nucleotide by the thiyl radical is returned to the same position.
  • The disulfide bridge is reduced by the action of thioredoxin.
  • Cf. EC 1.1.98.6 and EC 1.17.4.2.
 50 A0A0B4Q5Z1 A0A0B4Q636 A0A0S2MLX7 A0A0X9ZA49 A0A172XDN8 A0A181ZFZ8 A0A181ZH15 A0A1C8E6B1 A0A1L2JUA3 B9X2I1
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