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UniProt functional annotation for Q381M1 | ||
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| UniProt code: Q381M1. |
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| Organism: | |
Trypanosoma brucei brucei (strain 927/4 GUTat10.1). |
| Taxonomy: | |
Eukaryota; Discoba; Euglenozoa; Kinetoplastea; Metakinetoplastina; Trypanosomatida; Trypanosomatidae; Trypanosoma. |
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| Function: | |
Terminal uridylyltransferase which, specifically, catalyzes the addition of Us to the 3'-hydroxyl group of single-stranded RNAs with a 3'-terminal U. {ECO:0000269|PubMed:17189640, ECO:0000269|PubMed:17785418}. |
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| Catalytic activity: | |
Reaction=RNA(n) + UTP = diphosphate + RNA(n)-3'-uridine ribonucleotide; Xref=Rhea:RHEA:14785, Rhea:RHEA-COMP:11128, Rhea:RHEA-COMP:14648, ChEBI:CHEBI:33019, ChEBI:CHEBI:46398, ChEBI:CHEBI:83400, ChEBI:CHEBI:140627; EC=2.7.7.52; Evidence={ECO:0000269|PubMed:17189640, ECO:0000269|PubMed:17785418}; |
| Cofactor: | |
Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000269|PubMed:17189640, ECO:0000269|PubMed:17785418}; Name=Mn(2+); Xref=ChEBI:CHEBI:29035; Evidence={ECO:0000269|PubMed:17189640}; Note=Binds 1 Mg(2+) or Mn(2+) per subunit (PubMed:17189640, PubMed:17785418). The type of divalent cation used by the enzyme affects the nucleotide specificity; Mg(2+) induces predominantly uridine (U) incorporation while Mn(2+) induces also substantial incorporation of both adenine (A) and cytosine (C) (PubMed:17189640). {ECO:0000269|PubMed:17189640, ECO:0000269|PubMed:17785418}; |
| Activity regulation: | |
The 3' uridylated RNA substrate is involved in the selective incorporation of UTP; UTP binding is favored due to the constraint posed on the positioning of the NTP base by the continuous stacking interactions between Tyr-189 side chain, the bound NTP, and the terminal nucleoside base of the RNA substrate. {ECO:0000269|PubMed:17785418}. |
| Biophysicochemical properties: | |
Kinetic parameters: KM=1 uM for UTP (at 27 degrees Celsius and with 6(U) single-stranded RNA as substrate); KM=0.2 uM for 6(U) single-stranded RNA (at 27 degrees Celsius); Note=kcat is 0.5 min(-1) with UTP (PubMed:17189640). kcat is 0.3 min(-1) with 6(U) single-stranded RNA (PubMed:17189640). {ECO:0000269|PubMed:17189640}; |
| Subunit: | |
Monomer. {ECO:0000269|PubMed:17189640}. |
| Similarity: | |
Belongs to the DNA polymerase type-B-like family. {ECO:0000305}. |
Annotations taken from UniProtKB at the EBI.