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CATH Superfamily 3.20.70.20

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: waiting to be named.

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 5050: Putative adenosylcobalamin-dependent ribonucleosid...

There are 2 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-triphosphate reductase (thioredoxin). [EC: 1.17.4.2]
2'-deoxyribonucleoside triphosphate + thioredoxin disulfide + H(2)O = ribonucleoside triphosphate + thioredoxin.
  • The enzyme, characterized from the bacterium Lactobacillus leichmannii, is similar to class II ribonucleoside-diphosphate reductase (cf. EC 1.17.4.1); however, it is specific for the triphosphate versions of its substrates.
  • The enzyme contains an adenosylcobalamin cofactor that is involved in generation of a transient thiyl radical on a cysteine residue.
  • This radical 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.
 76 A0A061CCD5 A0A061CCD5 A0A061CRY2 A0A061CRY2 A0A087C078 A0A087C078 A0A0R1FFY7 A0A0R1FFY7 A0A0S4NLR4 A0A0S4NLR4
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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.
 48 A0A089Y2D4 A0A089Y2D4 A0A0C1M276 A0A0C1M276 A0A0E2BPL8 A0A0E2BPL8 A0A0U5JNY9 A0A0U5JNY9 A0A0U5JS34 A0A0U5JS34
(38 more...)
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