DnaQ-like (or DEDD) 3'-5' exonuclease domain superfamily; The DnaQ-like exonuclease superfamily is a structurally conserved group of 3'-5' exonucleases, which catalyze the excision of nucleoside monophosphates at the DNA or RNA termini in the 3'-5' direction. It is also called the DEDD superfamily, after the four invariant acidic residues present in the catalytic site of its members. The superfamily consists of DNA- and RNA-processing enzymes such as the proofreading domains of DNA polymerases, other DNA exonucleases, RNase D, RNase T, Oligoribonuclease and RNA exonucleases (REX). The DnaQ-like exonuclease domain contains three conserved sequence motifs termed ExoI, ExoII and ExoIII, which are clustered around the active site and contain four conserved acidic residues that serve as ligands for the two metal ions required for catalysis. The conservation patterns of the three motifs may vary among different subfamilies. DnaQ-like exonucleases are classified as DEDDy or DEDDh exonucleases depending on the variation of motif III as YX(3)D or HX(4)D, respectively. The significance of the motif differences is still unclear. Almost all RNase families in this superfamily are present only in eukaryotes and bacteria, but not in archaea, suggesting a later origin, which in some cases are accompanied by horizontal gene transfer.
The actual alignment was detected with superfamily member PRK05359:
Pssm-ID: 447876 Cd Length: 181 Bit Score: 224.26 E-value: 1.47e-75
DEDDh 3'-5' exonuclease domain of oligoribonuclease and similar proteins; Oligoribonuclease ...
8-181
8.24e-69
DEDDh 3'-5' exonuclease domain of oligoribonuclease and similar proteins; Oligoribonuclease (Orn) is a DEDDh-type DnaQ-like 3'-5' exoribonuclease that is responsible for degrading small oligoribonucleotides to mononucleotides. It contains three conserved sequence motifs termed ExoI, ExoII and ExoIII, with a specific Hx(4)D conserved pattern at ExoIII. These motifs are clustered around the active site and contain four conserved acidic residues that serve as ligands for the two metal ions required for catalysis. Orn is essential for Escherichia coli survival. The human homolog, also called Sfn (small fragment nuclease), is able to hydrolyze short single-stranded RNA and DNA oligomers. It plays a role in cellular nucleotide recycling.
Pssm-ID: 99838 [Multi-domain] Cd Length: 173 Bit Score: 207.01 E-value: 8.24e-69
DEDDh 3'-5' exonuclease domain of oligoribonuclease and similar proteins; Oligoribonuclease ...
8-181
8.24e-69
DEDDh 3'-5' exonuclease domain of oligoribonuclease and similar proteins; Oligoribonuclease (Orn) is a DEDDh-type DnaQ-like 3'-5' exoribonuclease that is responsible for degrading small oligoribonucleotides to mononucleotides. It contains three conserved sequence motifs termed ExoI, ExoII and ExoIII, with a specific Hx(4)D conserved pattern at ExoIII. These motifs are clustered around the active site and contain four conserved acidic residues that serve as ligands for the two metal ions required for catalysis. Orn is essential for Escherichia coli survival. The human homolog, also called Sfn (small fragment nuclease), is able to hydrolyze short single-stranded RNA and DNA oligomers. It plays a role in cellular nucleotide recycling.
Pssm-ID: 99838 [Multi-domain] Cd Length: 173 Bit Score: 207.01 E-value: 8.24e-69
DEDDh 3'-5' exonuclease domain family; DEDDh exonucleases, part of the DnaQ-like (or DEDD) ...
9-170
3.08e-05
DEDDh 3'-5' exonuclease domain family; DEDDh exonucleases, part of the DnaQ-like (or DEDD) exonuclease superfamily, catalyze the excision of nucleoside monophosphates at the DNA or RNA termini in the 3'-5' direction. These proteins contain four invariant acidic residues in three conserved sequence motifs termed ExoI, ExoII and ExoIII. DEDDh exonucleases are classified as such because of the presence of specific Hx(4)D conserved pattern at the ExoIII motif. The four conserved acidic residues are clustered around the active site and serve as ligands for the two metal ions required for catalysis. Most DEDDh exonucleases are the proofreading subunits (epsilon) or domains of bacterial DNA polymerase III, the main replicating enzyme in bacteria, which functions as the chromosomal replicase. Other members include other DNA and RNA exonucleases such as RNase T, Oligoribonuclease, and RNA exonuclease (REX), among others.
Pssm-ID: 176648 [Multi-domain] Cd Length: 159 Bit Score: 42.29 E-value: 3.08e-05
Database: CDSEARCH/cdd Low complexity filter: no Composition Based Adjustment: yes E-value threshold: 0.01
References:
Wang J et al. (2023), "The conserved domain database in 2023", Nucleic Acids Res.51(D)384-8.
Lu S et al. (2020), "The conserved domain database in 2020", Nucleic Acids Res.48(D)265-8.
Marchler-Bauer A et al. (2017), "CDD/SPARCLE: functional classification of proteins via subfamily domain architectures.", Nucleic Acids Res.45(D)200-3.
of the residues that compose this conserved feature have been mapped to the query sequence.
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