FEN-like PIN domains of bacteriophage T3, T4 RNase H, T5-5'nuclease, and homologs; PIN (PilT N ...
5-136
6.95e-07
FEN-like PIN domains of bacteriophage T3, T4 RNase H, T5-5'nuclease, and homologs; PIN (PilT N terminus) domain of bacteriophage T5-5'nuclease (5'-3' exonuclease or T5FEN), bacteriophage T4 RNase H (T4FEN), bacteriophage T3 (T3 phage exodeoxyribonuclease) and other similar 5' nucleases are included in this family. T5-5'nuclease is a 5'-3'exodeoxyribonuclease that also exhibits endonucleolytic activity on flap structures (branched duplex DNA containing a free single-stranded 5'end). T4 RNase H, which removes the RNA primers that initiate lagging strand fragments, has 5'- 3'exonuclease activity on DNA/DNA and RNA/DNA duplexes and has endonuclease activity on flap or forked DNA structures. Bacteriophage T3 is believed to function in the removal of DNA-linked RNA primers and is essential for phage DNA replication and also necessary for host DNA degradation and phage genetic recombination. These nucleases are members of the structure-specific, 5' nuclease family (FEN-like) that catalyzes hydrolysis of DNA duplex-containing nucleic acid structures during DNA replication, repair, and recombination. Canonical members of the FEN-like family possess a PIN domain with a two-helical structure insert (also known as the helical arch, helical clamp or I domain) of variable length (approximately 16 to 800 residues), and at the C-terminus of the PIN domain a H3TH (helix-3-turn-helix) domain, an atypical helix-hairpin-helix-2-like region. Both the H3TH domain (not included in this model) and the helical arch/clamp region are involved in DNA binding. The PIN domain belongs to a large nuclease superfamily. The structural properties of the PIN domain indicate its putative active center, consisting of invariant acidic amino acid residues (putative metal-binding residues), is geometrically similar in the active center of structure-specific 5' nucleases, PIN-domain ribonucleases of eukaryotic rRNA editing proteins, and bacterial toxins of toxin-antitoxin (TA) operons. In the T5-5'nuclease, structure-specific endonuclease activity requires binding of a single metal ion in the high-affinity, metal binding site 1, whereas exonuclease activity requires both, the high-affinity, metal binding site 1 and the low-affinity, metal binding site 2 to be occupied by a divalent cofactor. The T5-5'nuclease is reported to be able to bind several metal ions including, Mg2+, Mn2+, Zn2+ and Co2+, as co-factors.
Pssm-ID: 350210 Cd Length: 158 Bit Score: 47.59 E-value: 6.95e-07
FEN-like PIN domains of bacteriophage T3, T4 RNase H, T5-5'nuclease, and homologs; PIN (PilT N ...
5-136
6.95e-07
FEN-like PIN domains of bacteriophage T3, T4 RNase H, T5-5'nuclease, and homologs; PIN (PilT N terminus) domain of bacteriophage T5-5'nuclease (5'-3' exonuclease or T5FEN), bacteriophage T4 RNase H (T4FEN), bacteriophage T3 (T3 phage exodeoxyribonuclease) and other similar 5' nucleases are included in this family. T5-5'nuclease is a 5'-3'exodeoxyribonuclease that also exhibits endonucleolytic activity on flap structures (branched duplex DNA containing a free single-stranded 5'end). T4 RNase H, which removes the RNA primers that initiate lagging strand fragments, has 5'- 3'exonuclease activity on DNA/DNA and RNA/DNA duplexes and has endonuclease activity on flap or forked DNA structures. Bacteriophage T3 is believed to function in the removal of DNA-linked RNA primers and is essential for phage DNA replication and also necessary for host DNA degradation and phage genetic recombination. These nucleases are members of the structure-specific, 5' nuclease family (FEN-like) that catalyzes hydrolysis of DNA duplex-containing nucleic acid structures during DNA replication, repair, and recombination. Canonical members of the FEN-like family possess a PIN domain with a two-helical structure insert (also known as the helical arch, helical clamp or I domain) of variable length (approximately 16 to 800 residues), and at the C-terminus of the PIN domain a H3TH (helix-3-turn-helix) domain, an atypical helix-hairpin-helix-2-like region. Both the H3TH domain (not included in this model) and the helical arch/clamp region are involved in DNA binding. The PIN domain belongs to a large nuclease superfamily. The structural properties of the PIN domain indicate its putative active center, consisting of invariant acidic amino acid residues (putative metal-binding residues), is geometrically similar in the active center of structure-specific 5' nucleases, PIN-domain ribonucleases of eukaryotic rRNA editing proteins, and bacterial toxins of toxin-antitoxin (TA) operons. In the T5-5'nuclease, structure-specific endonuclease activity requires binding of a single metal ion in the high-affinity, metal binding site 1, whereas exonuclease activity requires both, the high-affinity, metal binding site 1 and the low-affinity, metal binding site 2 to be occupied by a divalent cofactor. The T5-5'nuclease is reported to be able to bind several metal ions including, Mg2+, Mn2+, Zn2+ and Co2+, as co-factors.
Pssm-ID: 350210 Cd Length: 158 Bit Score: 47.59 E-value: 6.95e-07
H3TH domain of the 5'-3' exonuclease of Taq DNA polymerase I and homologs; H3TH ...
167-192
3.49e-04
H3TH domain of the 5'-3' exonuclease of Taq DNA polymerase I and homologs; H3TH (helix-3-turn-helix) domains of the 5'-3' exonuclease (53EXO) of mutli-domain DNA polymerase I and single domain protein homologs are included in this family. Taq DNA polymerase I contains a polymerase domain for synthesizing a new DNA strand and a 53EXO domain for cleaving RNA primers or damaged DNA strands. Taq's 53EXO recognizes and endonucleolytically cleaves a structure-specific DNA substrate that has a bifurcated downstream duplex and an upstream template-primer duplex that overlaps the downstream duplex by 1 bp. The 53EXO cleaves the unpaired 5'-arm of the overlap flap DNA substrate. 5'-3' exonucleases are members of the structure-specific, 5' nuclease family that catalyzes hydrolysis of DNA duplex-containing nucleic acid structures during DNA replication, repair, and recombination. These nucleases contain a PIN (PilT N terminus) domain with a helical arch/clamp region/I domain (not included here) and inserted within the PIN domain is an atypical helix-hairpin-helix-2 (HhH2)-like region. This atypical HhH2 region, the H3TH domain, has an extended loop with at least three turns between the first two helices, and only three of the four helices appear to be conserved. Both the H3TH domain and the helical arch/clamp region are involved in DNA binding. Studies suggest that a glycine-rich loop in the H3TH domain contacts the phosphate backbone of the template strand in the downstream DNA duplex. The nucleases within this family have a carboxylate rich active site that is involved in binding essential divalent metal ion cofactors (i. e., Mg2+ or Mn2+ or Zn2+) required for nuclease activity. The first metal binding site is composed entirely of Asp/Glu residues from the PIN domain, whereas, the second metal binding site is composed generally of two Asp residues from the PIN domain and two Asp residues from the H3TH domain. Together with the helical arch and network of amino acids interacting with metal binding ions, the H3TH region defines a positively charged active-site DNA-binding groove in structure-specific 5' nucleases.
Pssm-ID: 188618 [Multi-domain] Cd Length: 73 Bit Score: 38.15 E-value: 3.49e-04
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.
Click on the triangle to view details about the feature, including a multiple sequence alignment
of your query sequence and the protein sequences used to curate the domain model,
where hash marks (#) above the aligned sequences show the location of the conserved feature residues.
The thumbnail image, if present, provides an approximate view of the feature's location in 3 dimensions.
Click on the triangle for interactive 3D structure viewing options.
Functional characterization of the conserved domain architecture found on the query.
Click here to see more details.
This image shows a graphical summary of conserved domains identified on the query sequence.
The Show Concise/Full Display button at the top of the page can be used to select the desired level of detail: only top scoring hits
(labeled illustration) or all hits
(labeled illustration).
Domains are color coded according to superfamilies
to which they have been assigned. Hits with scores that pass a domain-specific threshold
(specific hits) are drawn in bright colors.
Others (non-specific hits) and
superfamily placeholders are drawn in pastel colors.
if a domain or superfamily has been annotated with functional sites (conserved features),
they are mapped to the query sequence and indicated through sets of triangles
with the same color and shade of the domain or superfamily that provides the annotation. Mouse over the colored bars or triangles to see descriptions of the domains and features.
click on the bars or triangles to view your query sequence embedded in a multiple sequence alignment of the proteins used to develop the corresponding domain model.
The table lists conserved domains identified on the query sequence. Click on the plus sign (+) on the left to display full descriptions, alignments, and scores.
Click on the domain model's accession number to view the multiple sequence alignment of the proteins used to develop the corresponding domain model.
To view your query sequence embedded in that multiple sequence alignment, click on the colored bars in the Graphical Summary portion of the search results page,
or click on the triangles, if present, that represent functional sites (conserved features)
mapped to the query sequence.
Concise Display shows only the best scoring domain model, in each hit category listed below except non-specific hits, for each region on the query sequence.
(labeled illustration) Standard Display shows only the best scoring domain model from each source, in each hit category listed below for each region on the query sequence.
(labeled illustration) Full Display shows all domain models, in each hit category below, that meet or exceed the RPS-BLAST threshold for statistical significance.
(labeled illustration) Four types of hits can be shown, as available,
for each region on the query sequence:
specific hits meet or exceed a domain-specific e-value threshold
(illustrated example)
and represent a very high confidence that the query sequence belongs to the same protein family as the sequences use to create the domain model
non-specific hits
meet or exceed the RPS-BLAST threshold for statistical significance (default E-value cutoff of 0.01, or an E-value selected by user via the
advanced search options)
the domain superfamily to which the specific and non-specific hits belong
multi-domain models that were computationally detected and are likely to contain multiple single domains
Retrieve proteins that contain one or more of the domains present in the query sequence, using the Conserved Domain Architecture Retrieval Tool
(CDART).
Modify your query to search against a different database and/or use advanced search options