Summary: Domain of Unknown Function (DUF3856)
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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.
Role in biology
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. It is thus believed that many DUFs (or proteins of unknown function, PUFs) are only required under certain conditions.
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): 1148â€“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): 5857â€“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): e00744â€“e00713. doi:10.1128/mBio.00744-13. PMID 24381303.
- HÃ¤user, 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). Hughes, Diarmaid, ed. "RsfA (YbeB) Proteins Are Conserved Ribosomal Silencing Factors". PLoS Genetics 8 (7): e1002815. doi:10.1371/journal.pgen.1002815. PMC 3400551. PMID 22829778.
"DUF" families are annotated with the Domain of unknown function Wikipedia article. This is a general article, with no specific information about individual Pfam DUFs. If you have information about this particular DUF, please let us know using the "Add annotation" button below.
Domain of Unknown Function (DUF3856) Provide feedback
TPR-like protein. The 2hr2 structure belongs to the SCOP all alpha class, TPR-like superfamily, CT2138-like family. A DALI search gives hits with the putative peptidyl-prolyl isomerase 2fbn (Z=16), the SGTA protein (Z=16), the PLCR protein 2qfc (Z=16), a putative FK506-binding protein ( PDB:1qz2-A; DALI Z-score 15.3; RMSD 2.9; 16% sequence identity within 132 superimposed residues), and with the tetratricopeptide repeats of the protein phosphatase 5 ( PDB:2bug; DALI Z-score 15.1; RMSD 2.5; 19% sequence identity within 117 superimposed residues).
Internal database links
|SCOOP:||TPR_7 TPR_9 TPR_10 SNAP SRP_TPR_like|
|Similarity to PfamA using HHSearch:||TPR_11 TPR_11 TPR_12|
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR024552
This domain of unknown function is found in a small group of tetratricopeptide-like proteins, which includes the uncharacterised protein SWISSPROT. The structure of Q8KAL8 is known and belongs to the SCOP all alpha class, TPR-like superfamily, CT2138-like family.
- 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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Tetratricopeptide-like repeats are found in a numerous and diverse proteins involved in such functions as cell cycle regulation, transcriptional control, mitochondrial and peroxisomal protein transport, neurogenesis and protein folding.
The clan contains the following 127 members:Adaptin_N Alkyl_sulf_dimr ANAPC3 ANAPC5 API5 Arm Arm_2 Arm_3 Avirulence BTAD CAS_CSE1 ChAPs CLASP_N Clathrin Clathrin-link Clathrin_propel Cnd1 Cnd3 Coatomer_E Cohesin_HEAT Cohesin_load COPI_C CRM1_C Cse1 DNA_alkylation Drf_FH3 Drf_GBD DUF1822 DUF2225 DUF3385 DUF3458 DUF3808 DUF3856 DUF4042 DUF924 EST1 EST1_DNA_bind FAT Fis1_TPR_C Fis1_TPR_N Foie-gras_1 GUN4_N HAT HEAT HEAT_2 HEAT_EZ HEAT_PBS HemY_N IBB IBN_N IFRD KAP Leuk-A4-hydro_C LRV LRV_FeS MA3 MIF4G MIF4G_like MIF4G_like_2 Mo25 MRP-S27 NARP1 Neurochondrin Nipped-B_C Nro1 NSF Paf67 ParcG PC_rep PHAT PI3Ka PknG_TPR PPP5 PPR PPR_1 PPR_2 PPR_3 PPTA Proteasom_PSMB PUF Rab5-bind Rapsyn_N RPN7 Sel1 SHNi-TPR SNAP SPO22 SRP_TPR_like ST7 Suf SusD SusD-like SusD-like_2 SusD-like_3 TAF6_C TAtT Tcf25 TOM20_plant TPR_1 TPR_10 TPR_11 TPR_12 TPR_14 TPR_15 TPR_16 TPR_17 TPR_18 TPR_19 TPR_2 TPR_20 TPR_21 TPR_3 TPR_4 TPR_5 TPR_6 TPR_7 TPR_8 TPR_9 Upf2 V-ATPase_H_C V-ATPase_H_N Vac14_Fab1_bd Vitellogenin_N Vps39_1 W2 Xpo1 YfiO
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.
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Curation and family details
|Seed source:||JCSG structure PDB:2HR2|
|Number in seed:||7|
|Number in full:||12|
|Average length of the domain:||139.70 aa|
|Average identity of full alignment:||51 %|
|Average coverage of the sequence by the domain:||61.55 %|
|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:||3|
|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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There is 1 interaction for this family. More...
We determine these interactions using iPfam, which considers the interactions between residues in three-dimensional protein structures and maps those interactions back to Pfam families. You can find more information about the iPfam algorithm in the journal article that accompanies the website.
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 DUF3856 domain has been found. There are 6 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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