Protein Family Models

Members of this family catalyse the reduction of the 5,6-double bond of a uridine residue on tRNA. Dihydrouridine modification of tRNA is widely observed in prokaryotes and eukaryotes, and also in some archae. Most dihydrouridines are found in the D loop of t-RNAs. The role of dihydrouridine in tRNA is currently unknown, but may increase conformational flexibility of the tRNA. It is likely that different family members have different substrate specificities, which may overlap. Dus 1 (Swiss:Q9HGN6) from Saccharomyces cerevisiae acts on pre-tRNA-Phe, while Dus 2 (Swiss:P53720) acts on pre-tRNA-Tyr and pre-tRNA-Leu. Dus 1 is active as a single subunit, requiring NADPH or NADH, and is stimulated by the presence of FAD [1]. Some family members may be targeted to the mitochondria and even have a role in mitochondria [1]. [1]. 12003496. A conserved family of Saccharomyces cerevisiae synthases effects dihydrouridine modification of tRNA. Xing F, Martzen MR, Phizicky EM;. RNA 2002;8:370-381. (from Pfam)

Date:

2024-10-16

Gene:

dusA

Date:

2021-07-23

tRNA-dihydrouridine(20/20a) synthase DusA catalyzes the synthesis of 5,6-dihydrouridine (D), a modified base found in the D-loop of most tRNAs, via the reduction of the C5-C6 double bond in target uridines; specifically modifies U20 and U20a in tRNAs.

Date:

2023-03-02

This model represents one branch of COG0042 (Predicted TIM-barrel enzymes, possibly dehydrogenases, nifR3 family). It represents a distinct subset by a set of shared unique motifs, a conserved pattern of insertions/deletions relative to other nifR3 homologs, and by subclustering based on cross-genome bidirectional best hits. Members are found in species as diverse as the proteobacteria, a spirochete, a cyanobacterium, and Deinococcus radiodurans. NifR3 itself, a protein of unknown function associated with nitrogen regulation in Rhodobacter capsulatus, is not a member of this branch. Members of this family show a distant relationship to alpha/beta (TIM) barrel enzymes such as dihydroorotate dehydrogenase and glycolate oxidase.

Gene:

dusA

Date:

2024-05-17