ID   1.17.4.2
DE   ribonucleoside-triphosphate reductase (thioredoxin).
AN   ribonucleotide reductase.
CA   [thioredoxin]-disulfide + a 2'-deoxyribonucleoside 5'-triphosphate +
CA   H2O = [thioredoxin]-dithiol + a ribonucleoside 5'-triphosphate.
CC   -!- The enzyme, characterized from the bacterium Lactobacillus
CC       leichmannii, is similar to class II ribonucleoside-diphosphate
CC       reductase (cf. EC 1.17.4.1); however, it is specific for the
CC       triphosphate versions of its substrates.
CC   -!- The enzyme contains an adenosylcobalamin cofactor that is involved in
CC       generation of a transient thiyl (sulfanyl) radical on a cysteine
CC       residue.
CC   -!- This radical attacks the substrate, forming a ribonucleotide
CC       3'-radical, followed by water loss to form a ketyl (alpha-oxoacyl)
CC       radical.
CC   -!- The ketyl radical is reduced to 3'-keto-deoxynucleotide concomitant
CC       with formation of a disulfide anion radical between two cysteine
CC       residues.
CC   -!- A proton-coupled electron-transfer from the disulfide radical to the
CC       substrate generates a 3'-deoxynucleotide radical, and the the final
CC       product is formed when the hydrogen atom that was initially removed
CC       from the 3'-position of the nucleotide by the thiyl radical is
CC       returned to the same position.
CC   -!- The disulfide bridge is reduced by the action of thioredoxin. cf.
CC       EC 1.1.98.6.
DR   Q54CW7, RTPR_DICDI ;  Q2PDF6, RTPR_EUGGR ;  Q5FMX8, RTPR_LACAC ;
DR   Q1G7W2, RTPR_LACDA ;  Q04CQ7, RTPR_LACDB ;  Q041L3, RTPR_LACGA ;
DR   A8YW74, RTPR_LACH4 ;  Q59490, RTPR_LACLE ;  Q035U1, RTPR_LACP3 ;
DR   Q03PB4, RTPR_LEVBA ;  A6Q367, RTPR_NITSB ;  Q857H2, VG50_BPMB2 ;
DR   O64240, VG50_BPMD2 ;  Q05262, VG50_BPML5 ;
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