Summary: Putative restriction endonuclease
This is the Wikipedia entry entitled "Domain of unknown function". More...
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Domain of unknown function Edit Wikipedia article
A domain of unknown function (DUF) is a protein domain that has no characterised function. These families have been collected together in the Pfam database using the prefix DUF followed by a number, with examples being DUF2992 and DUF1220. There are now over 3,000 DUF families within the Pfam database representing over 20% of known families.
The DUF naming scheme was introduced by Chris Ponting, through the addition of DUF1 and DUF2 to the SMART database. These two domains were found to be widely distributed in bacterial signaling proteins. Subsequently, the functions of these domains were identified and they have since been renamed as the GGDEF domain and EAL domain respectively.
Structural genomics programmes have attempted to understand the function of DUFs through structure determination. The structures of over 250 DUF families have been solved. This work showed that about two thirds of DUF families had a structure similar to a previously solved one and therefore likely to be divergent members of existing protein superfamilies, whereas about one third possessed a novel protein fold.
Frequency and conservation
More than 20% of all protein domains were annotated as DUFs in 2013. About 2,700 DUFs are found in bacteria compared with just over 1,500 in eukaryotes. Over 800 DUFs are shared between bacteria and eukaryotes, and about 300 of these are also present in archaea. A total of 2,786 bacterial Pfam domains even occur in animals, including 320 DUFs.
Many DUFs are highly conserved, indicating an important role in biology. However, many such DUFs are not essential, hence their biological role often remains unknown. For instance, DUF143 is present in most bacteria and eukaryotic genomes. However, when it was deleted in Escherichia coli no obvious phenotype was obvious. Later it was shown that the proteins that contain DUF143, are ribosomal silencing factors that block the assembly of the two ribosomal subunits. While this function is not essential, it helps the cells to adapt to low nutrient conditions by shutting down protein biosynthesis. As a result, these proteins and the DUF only becomes relevant when the cells starve.
Essential DUFs (eDUFs)
Goodacre et al. identified 238 DUFs in 355 essential proteins (in 16 model bacterial species), most of which represent single-domain proteins, clearly establishing the biological essentiality of DUFs. These DUFs are called "essential DUFs" or eDUFs.
- Bateman A, Coggill P, Finn RD (October 2010). "DUFs: families in search of function". Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun. 66 (Pt 10): 1148–52. doi:10.1107/S1744309110001685. PMC 2954198. PMID 20944204.
- Schultz J, Milpetz F, Bork P, Ponting CP (May 1998). "SMART, a simple modular architecture research tool: identification of signaling domains". Proc. Natl. Acad. Sci. U.S.A. 95 (11): 5857–64. doi:10.1073/pnas.95.11.5857. PMC 34487. PMID 9600884.
- Jaroszewski L, Li Z, Krishna SS, et al. (September 2009). "Exploration of uncharted regions of the protein universe". PLoS Biol. 7 (9): e1000205. doi:10.1371/journal.pbio.1000205. PMC 2744874. PMID 19787035.
- Goodacre, N. F.; Gerloff, D. L.; Uetz, P. (2013). "Protein Domains of Unknown Function Are Essential in Bacteria". MBio 5 (1): e00744–e00713. doi:10.1128/mBio.00744-13. PMID 24381303.
- Häuser, R.; Pech, M.; Kijek, J.; Yamamoto, H.; Titz, B. R.; Naeve, F.; Tovchigrechko, A.; Yamamoto, K.; Szaflarski, W.; Takeuchi, N.; Stellberger, T.; Diefenbacher, M. E.; Nierhaus, K. H.; Uetz, P. (2012). "RsfA (YbeB) Proteins Are Conserved Ribosomal Silencing Factors". In Hughes, Diarmaid. PLoS Genetics 8 (7): e1002815. doi:10.1371/journal.pgen.1002815. PMC 3400551. PMID 22829778.
This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.
Putative restriction endonuclease Provide feedback
This family consists of hypothetical proteins that are greatly expanded in cyanobacteria. The proteins are found sporadically in other bacteria. A small number of member proteins also contain PF02861 domains that are involved in protein interactions. Solutions of several structures for members of this family show that it is likely to be acting as an endonuclease.
Kinch LN, Ginalski K, Rychlewski L, Grishin NV; , Nucleic Acids Res. 2005;33:3598-3605.: Identification of novel restriction endonuclease-like fold families among hypothetical proteins. PUBMED:15972856 EPMC:15972856
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR008538This entry consists of a number of hypothetical proteins from the Anabaena and Synechocystis cyanobacterial species.
The function of this protein is completely unknown. In a small number of proteins this protein also contains Clp_N domains (INTERPRO) that are involved in protein interactions.
- the number of sequences which exhibit this architecture
a textual description of the architecture, e.g. Gla, EGF x 2, Trypsin.
This example describes an architecture with one
Gladomain, followed by two consecutive
EGFdomains, and finally a single
- the UniProt description of the protein sequence
- the number of residues in the sequence
- the Pfam graphic itself.
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This clan includes a large number of nuclease families related to holliday junction resolvases [1,2].
The clan contains the following 123 members:BamHI BpuSI_N Bse634I BsuBI_PstI_RE Cas_APE2256 Cas_Cas02710 Cas_Cas4 Cas_Csm6 Cas_NE0113 CoiA Dna2 DpnII DRP DUF1016 DUF1052 DUF1064 DUF1626 DUF1703 DUF1780 DUF1853 DUF1887 DUF2034 DUF2130 DUF234 DUF2726 DUF2800 DUF2887 DUF3799 DUF3883 DUF4143 DUF4263 DUF4420 DUF506 DUF524 DUF559 DUF790 DUF91 DUF911 EcoRI EcoRII-C eIF-3_zeta Endonuc-BglII Endonuc-BsobI Endonuc-EcoRV Endonuc-FokI_C Endonuc-HincII Endonuc-MspI Endonuc-PvuII Endonuc_BglI Endonuc_Holl ERCC4 Exo5 Herpes_alk_exo Herpes_UL24 Hjc HSDR_N HSDR_N_2 L_protein_N McrBC Mrr_cat Mrr_cat_2 MutH MvaI_BcnI NaeI NARG2_C NERD NgoMIV_restric NotI PDDEXK_1 PDDEXK_2 PDDEXK_3 PDDEXK_4 PDDEXK_5 Pet127 Phage_endo_I R-HINP1I RAI1 RAP RE_AlwI RE_ApaLI RE_Bpu10I RE_Bsp6I RE_CfrBI RE_Eco47II RE_EcoO109I RE_HaeII RE_HindIII RE_HindVP RE_HpaII RE_LlaJI RE_LlaMI RE_MjaI RE_NgoBV RE_NgoPII RE_SacI RE_ScaI RE_SinI RE_TaqI RE_TdeIII RE_XamI RE_XcyI RecU RestrictionMunI RestrictionSfiI RmuC RNA_pol_Rpb5_N Sen15 SfsA TBPIP_N ThaI Tn7_Tnp_TnsA_N Transposase_31 tRNA_int_endo Tsp45I Uma2 UPF0102 VirArc_Nuclease VRR_NUC Vsr XhoI XisH YaeQ YqaJ
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
- alignment generated by searching the metagenomics sequence database using the family HMM
You can see the alignments as HTML or in three different sequence viewers:
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1Cannot generate PP/Heatmap alignments for seeds; no PP data available
Key: available, not generated, — not available.
Format an alignment
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Curation and family details
|Seed source:||Pfam-B_7809 (release 8.0) & Pfam-B_8730 (release 14.0)|
|Author:||Moxon SJ, Bateman A|
|Number in seed:||170|
|Number in full:||4083|
|Average length of the domain:||163.40 aa|
|Average identity of full alignment:||17 %|
|Average coverage of the sequence by the domain:||81.91 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||7|
|Download:||download the raw HMM for this family|
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The tree shows the occurrence of this domain across different species. More...
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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 Uma2 domain has been found. There are 7 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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