Summary: Topoisomerase I zinc-ribbon-like
Topoisomerase I zinc-ribbon-like Provide feedback
Some Proteobacteria topoisomerase I contain two zinc-ribbon-like domains at the C-terminus that structurally homologous to PF01396. However, this domain no longer bind zinc. Indeed, only one of the four cysteine residues remains .
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR013263
DNA topoisomerases regulate the number of topological links between two DNA strands (i.e. change the number of superhelical turns) by catalysing transient single- or double-strand breaks, crossing the strands through one another, then resealing the breaks [PUBMED:7770916]. These enzymes have several functions: to remove DNA supercoils during transcription and DNA replication; for strand breakage during recombination; for chromosome condensation; and to disentangle intertwined DNA during mitosis [PUBMED:12042765, PUBMED:11395412]. DNA topoisomerases are divided into two classes: type I enzymes (EC; topoisomerases I, III and V) break single-strand DNA, and type II enzymes (EC; topoisomerases II, IV and VI) break double-strand DNA [PUBMED:12596227].
Type I topoisomerases are ATP-independent enzymes (except for reverse gyrase), and can be subdivided according to their structure and reaction mechanisms: type IA (bacterial and archaeal topoisomerase I, topoisomerase III and reverse gyrase) and type IB (eukaryotic topoisomerase I and topoisomerase V). These enzymes are primarily responsible for relaxing positively and/or negatively supercoiled DNA, except for reverse gyrase, which can introduce positive supercoils into DNA.
This entry represents the C-terminal zinc-ribbon-like domain found in bacterial topoisomerase I (type IA) enzymes. Escherichia coli topoisomerase I proteins contain five copies of a zinc-ribbon-like domain at their C terminus, two of which have lost their cysteine residues and are therefore probably not able to bind zinc [PUBMED:10873443]. This domain is still considered to be a member of the zinc-ribbon superfamily despite not being able to bind zinc.
More information about this protein can be found at Protein of the Month: DNA Topoisomerase [PUBMED:].
|Cellular component||chromosome (GO:0005694)|
|Molecular function||DNA binding (GO:0003677)|
|DNA topoisomerase type II (ATP-hydrolyzing) activity (GO:0003918)|
|Biological process||DNA topological change (GO:0006265)|
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This example describes an architecture with one
Gladomain, followed by two consecutive
EGFdomains, and finally a single
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A clan of zinc-binding ribbon domains.
The clan contains the following 70 members:A2L_zn_ribbon Auto_anti-p27 Baculo_LEF5_C CpXC DNA_RNApol_7kD DUF1451 DUF1610 DUF1936 DUF2072 DUF2116 DUF2180 DUF2387 DUF2614 DUF35_N DUF4379 DZR Elf1 GATA Lar_restr_allev Mu-like_Com NinF NOB1_Zn_bind Nudix_N_2 Ogr_Delta OrfB_Zn_ribbon PhnA_Zn_Ribbon Prim_Zn_Ribbon Ribosomal_L32p Ribosomal_L37ae Ribosomal_S27 Ribosomal_S27e RNA_POL_M_15KD RRN7 Spt4 TF_Zn_Ribbon TFIIS_C Tnp_zf-ribbon_2 Topo_Zn_Ribbon Toprim_Crpt Trm112p UPF0547 zf-C4_Topoisom zf-CHC2 zf-CSL zf-DHHC zf-dskA_traR zf-FPG_IleRS zf-GRF zf-ISL3 zf-NADH-PPase zf-RanBP zf-ribbon_3 zf-TFIIB zf-trcl zf-ZPR1 zinc-ribbon_6 zinc-ribbons_6 zinc_ribbon_10 zinc_ribbon_11 zinc_ribbon_12 zinc_ribbon_13 zinc_ribbon_15 zinc_ribbon_2 zinc_ribbon_4 zinc_ribbon_5 zinc_ribbon_9 Zn-ribbon_8 Zn_ribbon_recom Zn_Tnp_IS1 Zn_Tnp_IS1595
We make a range of alignments for each Pfam-A family:
- the curated alignment from which the HMM for the family is built
- the alignment generated by searching the sequence database using the HMM
- Representative Proteomes (RPs) at 15%, 35%, 55% and 75% co-membership thresholds
- alignment generated by searching the NCBI sequence database using the family HMM
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Curation and family details
|Seed source:||Pfam-B_5615 (release 17.0)|
|Number in seed:||64|
|Number in full:||9958|
|Average length of the domain:||39.00 aa|
|Average identity of full alignment:||48 %|
|Average coverage of the sequence by the domain:||9.07 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 80369284 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||7|
|Download:||download the raw HMM for this family|
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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Topo_Zn_Ribbon domain has been found. There are 2 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.
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