Summary: DNA methylase
Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.
This is the Wikipedia entry entitled "DNA methyltransferase". More...
The Wikipedia text that you see displayed here is a download from Wikipedia. This means that the information we display is a copy of the information from the Wikipedia database. The button next to the article title ("Edit Wikipedia article") takes you to the edit page for the article directly within Wikipedia. You should be aware you are not editing our local copy of this information. Any changes that you make to the Wikipedia article will not be displayed here until we next download the article from Wikipedia. We currently download new content on a nightly basis.
Does Pfam agree with the content of the Wikipedia entry ?
Pfam has chosen to link families to Wikipedia articles. In some case we have created or edited these articles but in many other cases we have not made any direct contribution to the content of the article. The Wikipedia community does monitor edits to try to ensure that (a) the quality of article annotation increases, and (b) vandalism is very quickly dealt with. However, we would like to emphasise that Pfam does not curate the Wikipedia entries and we cannot guarantee the accuracy of the information on the Wikipedia page.
Editing Wikipedia articles
Before you edit for the first time
Wikipedia is a free, online encyclopedia. Although anyone can edit or contribute to an article, Wikipedia has some strong editing guidelines and policies, which promote the Wikipedia standard of style and etiquette. Your edits and contributions are more likely to be accepted (and remain) if they are in accordance with this policy.
You should take a few minutes to view the following pages:
How your contribution will be recorded
Anyone can edit a Wikipedia entry. You can do this either as a new user or you can register with Wikipedia and log on. When you click on the "Edit Wikipedia article" button, your browser will direct you to the edit page for this entry in Wikipedia. If you are a registered user and currently logged in, your changes will be recorded under your Wikipedia user name. However, if you are not a registered user or are not logged on, your changes will be logged under your computer's IP address. This has two main implications. Firstly, as a registered Wikipedia user your edits are more likely seen as valuable contribution (although all edits are open to community scrutiny regardless). Secondly, if you edit under an IP address you may be sharing this IP address with other users. If your IP address has previously been blocked (due to being flagged as a source of 'vandalism') your edits will also be blocked. You can find more information on this and creating a user account at Wikipedia.
If you have problems editing a particular page, contact us at email@example.com and we will try to help.
The community annotation is a new facility of the Pfam web site. If you have problems editing or experience problems with these pages please contact us.
DNA methyltransferase Edit Wikipedia article
|N-6 DNA Methylase|
crystal structure of type i restriction enzyme ecoki m protein (ec 184.108.40.206) (m.ecoki)
|HsdM N-terminal domain|
|C-5 cytosine-specific DNA methylase|
structure of human dnmt2, an enigmatic dna methyltransferase homologue
crystal structure of methyltransferase mboiia (moraxella bovis)
In biochemistry, the DNA methyltransferase (DNA MTase) family of enzymes catalyze the transfer of a methyl group to DNA. DNA methylation serves a wide variety of biological functions. All the known DNA methyltransferases use S-adenosyl methionine (SAM) as the methyl donor.
MTases can be divided into three different groups on the basis of the chemical reactions they catalyze:
- m6A - those that generate N6-methyladenine EC 220.127.116.11
- m4C - those that generate N4-methylcytosine EC 18.104.22.168
- m5C - those that generate C5-methylcytosine EC 22.214.171.124
m6A and m4C methyltransferases are found primarily in prokaryotes. m5C methyltransfereases are found in some lower eukaryotes, in most higher plants, and in animals beginning with the echinoderms. The m6A methyltransferases (N-6 adenine-specific DNA methylase) (A-Mtase) are enzymes that specifically methylate the amino group at the C-6 position of adenines in DNA. They are found in the three existing types of bacterial restriction-modification systems (in type I system the A-Mtase is the product of the hsdM gene, and in type III it is the product of the mod gene). These enzymes are responsible for the methylation of specific DNA sequences in order to prevent the host from digesting its own genome via its restriction enzymes. These methylases have the same sequence specificity as their corresponding restriction enzymes. These enzymes contain a conserved motif Asp/Asn-Pro-Pro-Tyr/Phe in their N-terminal section, this conserved region could be involved in substrate binding or in the catalytic activity. The structure of N6-MTase TaqI (M.TaqI) has been resolved to 2.4 A. The molecule folds into 2 domains, an N-terminal catalytic domain, which contains the catalytic and cofactor binding sites, and comprises a central 9-stranded beta-sheet, surrounded by 5 helices; and a C-terminal DNA recognition domain, which is formed by 4 small beta-sheets and 8 alpha-helices. The N- and C-terminal domains form a cleft that accommodates the DNA substrate. A classification of N-MTases has been proposed, based on conserved motif (CM) arrangements. According to this classification, N6-MTases that have a DPPY motif (CM II) occurring after the FxGxG motif (CM I) are designated D12 class N6-adenine MTases. The type I restriction and modification system is composed of three polypeptides R, M and S. The M (hsdM) and S subunits together form a methyltransferase that methylates two adenine residues in complementary strands of a bipartite DNA recognition sequence. In the presence of the R subunit, the complex can also act as an endonuclease, binding to the same target sequence but cutting the DNA some distance from this site. Whether the DNA is cut or modified depends on the methylation state of the target sequence. When the target site is unmodified, the DNA is cut. When the target site is hemimethylated, the complex acts as a maintenance methyltransferase, modifying the DNA so that both strands become methylated. hsdM contains an alpha-helical domain at the N-terminus, the HsdM N-terminal domain.
m4C methyltransferases (N-4 cytosine-specific DNA methylases) are enzymes that specifically methylate the amino group at the C-4 position of cytosines in DNA. Such enzymes are found as components of type II restriction-modification systems in prokaryotes. Such enzymes recognise a specific sequence in DNA and methylate a cytosine in that sequence. By this action they protect DNA from cleavage by type II restriction enzymes that recognise the same sequence
m5C methyltransferases (C-5 cytosine-specific DNA methylase) (C5 Mtase) are enzymes that specifically methylate the C-5 carbon of cytosines in DNA to produce C5-methylcytosine. In mammalian cells, cytosine-specific methyltransferases methylate certain CpG sequences, which are believed to modulate gene expression and cell differentiation. In bacteria, these enzymes are a component of restriction-modification systems and serve as valuable tools for the manipulation of DNA. The structure of HhaI methyltransferase (M.HhaI) has been resolved to 2.5 A: the molecule folds into 2 domains - a larger catalytic domain containing catalytic and cofactor binding sites, and a smaller DNA recognition domain.
De novo vs. maintenance
De novo methyltransferases recognize something in the DNA that allows them to newly methylate cytosines. These are expressed mainly in early embryo development and they set up the pattern of methylation.
Maintenance methyltransferases add methylation to DNA when one strand is already methylated. These work throughout the life of the organism to maintain the methylation pattern that had been established by the de novo methyltransferases.
Three active DNA methyltransferases have been identified in mammals. They are named DNMT1, DNMT3A, and DNMT3B. A fourth enzyme previously known as DNMT2 is not a DNA methyltransferase (see below).
DNMT1 is the most abundant DNA methyltransferase in mammalian cells, and considered to be the key maintenance methyltransferase in mammals. It predominantly methylates hemimethylated CpG di-nucleotides in the mammalian genome. This enzyme is 7– to 100-fold more active on hemimethylated DNA as compared with unmethylated substrate in vitro, but it is still more active at de novo methylation than other DNMTs. The recognition motif for the human enzyme involves only three of the bases in the CpG dinucleotide pair: a C on one strand and CpG on the other. This relaxed substrate specificity requirement allows it to methylate unusual structures like DNA slippage intermediates at de novo rates that equal its maintenance rate. Like other DNA cytosine-5 methyltransferases the human enzyme recognizes flipped out cytosines in double stranded DNA and operates by the nucleophilic attack mechanism. In human cancer cells DNMT1 is responsible for both de novo and maintenance methylation of tumor suppressor genes. The enzyme is about 1,620 amino acids long. The first 1,100 amino acids constitute the regulatory domain of the enzyme, and the remaining residues constitute the catalytic domain. These are joined by Gly-Lys repeats. Both domains are required for the catalytic function of DNMT1.
DNMT1 has several isoforms, the somatic DNMT1, a splice variant (DNMT1b) and an oocyte-specific isoform (DNMT1o). DNMT1o is synthesized and stored in the cytoplasm of the oocyte and translocated to the cell nucleus during early embryonic development, while the somatic DNMT1 is always found in the nucleus of somatic tissue.
DNMT1 null mutant embryonic stem cells were viable and contained a small percentage of methylated DNA and methyltransferase activity. Mouse embryos homozygous for a deletion in Dnmt1 die at 10–11 days gestation.
Although this enzyme has strong sequence similarities with 5-methylcytosine methyltransferases of both prokaryotes and eukaryotes, in 2006, the enzyme was shown to methylate position 38 in aspartic acid transfer RNA and does not methylate DNA. To reflect this different function, the name for this methyltransferase has been changed to TRDMT1 (tRNA aspartic acid methyltransferase 1) to better reflect its biological function. TRDMT1 is the first RNA cytosine methyltransferase to be identified in a human.
|This section does not cite any sources. (November 2010)|
DNMT3 is a family of DNA methyltransferases that could methylate hemimethylated and unmethylated CpG at the same rate. The architecture of DNMT3 enzymes is similar to that of DNMT1, with a regulatory region attached to a catalytic domain. There are three known members of the DNMT3 family: DNMT3a, 3b, and 3L.
DNMT3a and DNMT3b can mediate methylation-independent gene repression. DNMT3a can co-localize with heterochromatin protein (HP1) and methyl-CpG-binding protein (MeCBP). They can also interact with DNMT1, which might be a co-operative event during DNA methylation. DNMT3a prefers CpG methylation to CpA, CpT, and CpC methylation, though there appears to be some sequence preference of methylation for DNMT3a and DNMT3b. DNMT3a methylates CpG sites at a rate much slower than DNMT1, but greater than DNMT3b.
DNMT3L contains DNA methyltransferase motifs and is required for establishing maternal genomic imprints, despite being catalytically inactive. DNMT3L is expressed during gametogenesis when genomic imprinting takes place. The loss of DNMT3L leads to bi-allelic expression of genes normally not expressed by the maternal allele. DNMT3L interacts with DNMT3a and DNMT3b and co-localized in the nucleus. Though DNMT3L appears incapable of methylation, it may participate in transcriptional repression.
- Vidaza (azacitidine) in phase III trials for Myelodysplastic Syndromes and AML
- Dacogen (decitabine) in phase III trials for AML and CML
- Loenen WA, Daniel AS, Braymer HD, Murray NE (November 1987). "Organization and sequence of the hsd genes of Escherichia coli K-12". J. Mol. Biol. 198 (2): 159–70. doi:10.1016/0022-2836(87)90303-2. PMID 3323532.
- Narva KE, Van Etten JL, Slatko BE, Benner JS (December 1988). "The amino acid sequence of the eukaryotic DNA [N6-adenine]methyltransferase, M.CviBIII, has regions of similarity with the prokaryotic isoschizomer M.TaqI and other DNA [N6-adenine] methyltransferases". Gene 74 (1): 253–9. doi:10.1016/0378-1119(88)90298-3. PMID 3248728.
- Lauster R (March 1989). "Evolution of type II DNA methyltransferases. A gene duplication model". J. Mol. Biol. 206 (2): 313–21. doi:10.1016/0022-2836(89)90481-6. PMID 2541254.
- Timinskas A, Butkus V, Janulaitis A (May 1995). "Sequence motifs characteristic for DNA [cytosine-N4] and DNA [adenine-N6] methyltransferases. Classification of all DNA methyltransferases". Gene 157 (1–2): 3–11. doi:10.1016/0378-1119(94)00783-O. PMID 7607512.
- Labahn J, Granzin J, Schluckebier G, Robinson DP, Jack WE, Schildkraut I, Saenger W (November 1994). "Three-dimensional structure of the adenine-specific DNA methyltransferase M.Taq I in complex with the cofactor S-adenosylmethionine". Proc. Natl. Acad. Sci. U.S.A. 91 (23): 10957–61. doi:10.1073/pnas.91.23.10957. PMC 45145. PMID 7971991.
- Kelleher JE, Daniel AS, Murray NE (1991). "Mutations that confer de novo activity upon a maintenance methyltransferase". Journal of Molecular Biology 221 (2): 431–440. doi:10.1016/0022-2836(91)80064-2. PMID 1833555.
- Pósfai J, Bhagwat AS, Roberts RJ (December 1988). "Sequence motifs specific for cytosine methyltransferases". Gene 74 (1): 261–5. doi:10.1016/0378-1119(88)90299-5. PMID 3248729.
- Kumar S, Cheng X, Klimasauskas S, Mi S, Posfai J, Roberts RJ, Wilson GG (January 1994). "The DNA (cytosine-5) methyltransferases". Nucleic Acids Res. 22 (1): 1–10. doi:10.1093/nar/22.1.1. PMC 307737. PMID 8127644.
- Lauster R, Trautner TA, Noyer-Weidner M (March 1989). "Cytosine-specific type II DNA methyltransferases. A conserved enzyme core with variable target-recognizing domains". J. Mol. Biol. 206 (2): 305–12. doi:10.1016/0022-2836(89)90480-4. PMID 2716049.
- Cheng X (February 1995). "DNA modification by methyltransferases". Curr. Opin. Struct. Biol. 5 (1): 4–10. doi:10.1016/0959-440X(95)80003-J. PMID 7773746.
- Cheng X, Kumar S, Posfai J, Pflugrath JW, Roberts RJ (July 1993). "Crystal structure of the HhaI DNA methyltransferase complexed with S-adenosyl-L-methionine". Cell 74 (2): 299–307. doi:10.1016/0092-8674(93)90421-L. PMID 8343957.
- "DNMT1". Gene Symbol Report. HUGO Gene Nomenclature Committee. Retrieved 2012-09-27.
- "DNMT3A". Gene Symbol Report. HUGO Gene Nomenclature Committee. Retrieved 2012-09-27.
- "DNMT3B". Gene Symbol Report. HUGO Gene Nomenclature Committee. Retrieved 2012-09-27.
- "DNMT3L". Gene Symbol Report. HUGO Gene Nomenclature Committee. Retrieved 2012-09-27.
- Kho MR, Baker DJ, Laayoun A, Smith SS (1998). "Stalling of Human DNA (Cytosine-5) Methyltransferase at Single Strand Conformers form a Site of Dynamic Mutation". Journal of Molecular Biology 275 (1): 67–79. doi:10.1006/jmbi.1997.1430. PMID 9451440.
- Smith SS, Kaplan BE, Sowers LC, Newman EM (1992). "Mechanism of human methyl-directed DNA methyltransferase and the fidelity of cytosine methylation". Proceedings of the National Academy of Sciences of the United States of America 89 (10): 4748–4744. doi:10.1073/pnas.89.10.4744. PMC 49160. PMID 1584813.
- Jair KW, Bachman KE, Suzuki H, Ting AH, Rhee I, Yen RW, Baylin SB, Schuebel KE (2006). "De novo CpG Island Methylation in Human Cancer Cells". Cancer Research 69 (2): 682–692. doi:10.1158/0008-5472.CAN-05-1980. PMID 16423997.
- Ting AH, Jair KW, Schuebel KE, Baylin SB (2006). "Differential Requirement for DNA Methyltransferse 1 In Maintianing Cancer Cell Gene Promoter Hypermethylation". Cancer Research 66 (2): 729–735. doi:10.1158/0008-5472.CAN-05-1537. PMID 16424002.
- Li E, Bestor TH, Jaenisch R (1992). "Targeted Mutation of the DNA Methyltransferase Gene Results in Embryonic Lethality". Cell 69 (6): 915–926. doi:10.1016/0092-8674(92)90611-F. PMID 1606615.
- Goll MG, Kirpekar F, Maggert KA, Yoder JA, Hsieh CL, Zhang X, Golic KG, Jacobsen SE, Bestor TH (2006). "Methylation of tRNAAsp by the DNA Methyltransferase Homolog Dnmt2". Science 311 (5759): 395–398. doi:10.1126/science.1120976. PMID 16424344.
- "TRDMT1 tRNA aspartic acid methyltransferase 1 (Homo sapiens)". Entrez Gene. NCBI. 2010-11-01. Retrieved 2010-11-07.
- Mack GS (2010). "To selectivity and beyond". Nat. Biotechnol. 28 (12): 1259–66. doi:10.1038/nbt.1724. PMID 21139608.
- Smith SS (1994). "Biological implications of the mechanism of action of human DNA (cytosine-5)methyltransferase". Prog. Nucleic Acid Res. Mol. Biol. 49: 65–111. PMID 7863011.
- Pradhan S, Esteve PO (2003). "Mammalian DNA (cytosine-5) methyltransferases and their expression". Clin. Immunol. 109 (1): 6–16. doi:10.1016/S1521-6616(03)00204-3. PMID 14585271.
- Goll MG, Bestor TH (2005). "Eukaryotic cytosine methyltransferases". Annu. Rev. Biochem. 74: 481–514. doi:10.1146/annurev.biochem.74.010904.153721. PMID 15952895.
- Svedruzić ZM (2008). "Mammalian cytosine DNA methyltransferase Dnmt1: enzymatic mechanism, novel mechanism-based inhibitors, and RNA-directed DNA methylation". Curr. Med. Chem. 15 (1): 92–106. doi:10.2174/092986708783330700. PMID 18220765.
- Information about DNA methyltransferases and DNA methylation at epigeneticstation.com
- Data for a DNA methyltransferase (DNMT) Antibody
- DNA Modification Methyltransferases at the US National Library of Medicine Medical Subject Headings (MeSH)
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.
DNA methylase Provide feedback
Members of this family are DNA methylases. The family contains both N-4 cytosine-specific DNA methylases and N-6 Adenine-specific DNA methylases.
Internal database links
|SCOOP:||MethyltransfD12 N6_Mtase Met_10 Cons_hypoth95 RsmJ tRNA_U5-meth_tr N6-adenineMlase|
|Similarity to PfamA using HHSearch:||UPF0020|
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR002941
This domain is found in DNA methylases. In prokaryotes, the major role of DNA methylation is to protect host DNA against degradation by restriction enzymes. This family contains both N-4 cytosine-specific DNA methylases and N-6 Adenine-specific DNA methylases. N-4 cytosine-specific DNA methylases (EC) [PUBMED:7607512] are enzymes that specifically methylate the amino group at the C-4 position of cytosines in DNA. Such enzymes are found as components of type II restriction-modification systems in prokaryotes. Such enzymes recognise a specific sequence in DNA and methylate a cytosine in that sequence. By this action they protect DNA from cleavage by type II restriction enzymes that recognise the same sequence. N-6 adenine-specific DNA methylases (EC) (A-Mtase) are enzymes that specifically methylate the amino group at the C-6 position of adenines in DNA. Such enzymes are found in the three existing types of bacterial restriction-modification systems (in type I system the A-Mtase is the product of the hsdM gene, and in type III it is the product of the mod gene). All of these enzymes recognise a specific sequence in DNA and methylate an adenine in that sequence.
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Molecular function||DNA binding (GO:0003677)|
|N-methyltransferase activity (GO:0008170)|
|Biological process||DNA methylation (GO:0006306)|
Below is a listing of the unique domain organisations or architectures in which this domain is found. More...
The graphic that is shown by default represents the longest sequence with a given architecture. Each row contains the following information:
- 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
- a link to the page in the Pfam site showing information about the sequence that the graphic describes
- the UniProt description of the protein sequence
- the number of residues in the sequence
- the Pfam graphic itself.
Note that you can see the family page for a particular domain by clicking on the graphic. You can also choose to see all sequences which have a given architecture by clicking on the Show link in each row.
Finally, because some families can be found in a very large number of architectures, we load only the first fifty architectures by default. If you want to see more architectures, click the button at the bottom of the page to load the next set.
Loading domain graphics...
A class of redox enzymes are two domain proteins. One domain, termed the catalytic domain, confers substrate specificity and the precise reaction of the enzyme. The other domain, which is common to this class of redox enzymes, is a Rossmann-fold domain. The Rossmann domain binds nicotinamide adenine dinucleotide (NAD+) and it is this cofactor that reversibly accepts a hydride ion, which is lost or gained by the substrate in the redox reaction. Rossmann domains have an alpha/beta fold, which has a central beta sheet, with approximately five alpha helices found surrounding the beta sheet.The strands forming the beta sheet are found in the following characteristic order 654123. The inter sheet crossover of the stands in the sheet form the NAD+ binding site . In some more distantly relate Rossmann domains the NAD+ cofactor is replaced by the functionally similar cofactor FAD.
The clan contains the following 184 members:2-Hacid_dh_C 3Beta_HSD 3HCDH_N adh_short adh_short_C2 ADH_zinc_N ADH_zinc_N_2 AdoHcyase_NAD AdoMet_MTase AlaDh_PNT_C Amino_oxidase ApbA AviRa B12-binding Bac_GDH Bin3 Bmt2 CheR CMAS CmcI CoA_binding CoA_binding_2 CoA_binding_3 Cons_hypoth95 DAO DapB_N DFP DNA_methylase DOT1 DREV DUF1442 DUF166 DUF1776 DUF2431 DUF268 DUF364 DUF43 DUF5129 DUF5130 DUF938 DXP_redisom_C DXP_reductoisom Eco57I ELFV_dehydrog Eno-Rase_FAD_bd Eno-Rase_NADH_b Enoyl_reductase Epimerase F420_oxidored FAD_binding_2 FAD_binding_3 FAD_oxidored Fibrillarin FMO-like FmrO FtsJ G6PD_N GCD14 GDI GDP_Man_Dehyd GFO_IDH_MocA GIDA GidB GLF Glu_dehyd_C Glyco_hydro_4 GMC_oxred_N Gp_dh_N GRAS GRDA HI0933_like HIM1 IlvN K_oxygenase KR LCM Ldh_1_N Lycopene_cycl Malic_M Mannitol_dh MCRA Met_10 Methyltr_RsmB-F Methyltrans_Mon Methyltrans_SAM Methyltransf_10 Methyltransf_11 Methyltransf_12 Methyltransf_15 Methyltransf_16 Methyltransf_17 Methyltransf_18 Methyltransf_19 Methyltransf_2 Methyltransf_20 Methyltransf_21 Methyltransf_22 Methyltransf_23 Methyltransf_24 Methyltransf_25 Methyltransf_28 Methyltransf_29 Methyltransf_3 Methyltransf_30 Methyltransf_31 Methyltransf_32 Methyltransf_34 Methyltransf_4 Methyltransf_5 Methyltransf_7 Methyltransf_8 Methyltransf_9 Methyltransf_PK MethyltransfD12 MetW Mg-por_mtran_C MOLO1 Mqo MT-A70 MTS Mur_ligase N2227 N6-adenineMlase N6_Mtase N6_N4_Mtase NAD_binding_10 NAD_binding_2 NAD_binding_3 NAD_binding_4 NAD_binding_5 NAD_binding_7 NAD_binding_8 NAD_binding_9 NAD_Gly3P_dh_N NAS NmrA NNMT_PNMT_TEMT NodS NSP13 OCD_Mu_crystall PARP_regulatory PCMT PDH Polysacc_synt_2 Pox_MCEL Prenylcys_lyase PrmA PRMT5 Pyr_redox Pyr_redox_2 Pyr_redox_3 RmlD_sub_bind Rossmann-like rRNA_methylase RrnaAD Rsm22 RsmJ Sacchrp_dh_NADP SAM_MT SAMBD SE Semialdhyde_dh Shikimate_DH Spermine_synth TehB THF_DHG_CYH_C Thi4 ThiF TPM_phosphatase TPMT TrkA_N TRM TRM13 TrmK tRNA_U5-meth_tr Trp_halogenase TylF Ubie_methyltran UDPG_MGDP_dh_N UPF0020 UPF0146 V_cholerae_RfbT XdhC_C YjeF_N
We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the UniProtKB sequence database, the NCBI sequence database, and our metagenomics sequence database. More...
There are various ways to view or download the sequence alignments that we store. We provide several sequence viewers and a plain-text Stockholm-format file for download.
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 UniProtKB sequence database using the family HMM
- 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:
- a Java applet developed at the University of Dundee. You will need Java installed before running jalview
- an HTML page showing the whole alignment.Please note: full Pfam alignments can be very large. These HTML views are extremely large and often cause problems for browsers. Please use either jalview or the Pfam viewer if you have trouble viewing the HTML version
- an HTML-based representation of the alignment, coloured according to the posterior-probability (PP) values from the HMM. As for the standard HTML view, heatmap alignments can also be very large and slow to render.
You can download (or view in your browser) a text representation of a Pfam alignment in various formats:
You can also change the order in which sequences are listed in the alignment, change how insertions are represented, alter the characters that are used to represent gaps in sequences and, finally, choose whether to download the alignment or to view it in your browser directly.
You may find that large alignments cause problems for the viewers and the reformatting tool, so we also provide all alignments in Stockholm format. You can download either the plain text alignment, or a gzipped version of it.
We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.
1Cannot generate PP/Heatmap alignments for seeds; no PP data available
Key: available, not generated, — not available.
Format an alignment
We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.
You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.
HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...
If you find these logos useful in your own work, please consider citing the following article:
This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.
Note: You can also download the data file for the tree.
Curation and family details
This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.
|Seed source:||Pfam-B_164 (release 4.0)|
|Number in seed:||49|
|Number in full:||4182|
|Average length of the domain:||212.60 aa|
|Average identity of full alignment:||18 %|
|Average coverage of the sequence by the domain:||55.38 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 17690987 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||16|
|Download:||download the raw HMM for this family|
Weight segments by...
Change the size of the sunburst
selected sequences to HMM
a FASTA-format file
- 0 sequences
- 0 species
This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the More....
This chart is a modified "sunburst" visualisation of the species tree for this family. It shows each node in the tree as a separate arc, arranged radially with the superkingdoms at the centre and the species arrayed around the outermost ring.
How the sunburst is generated
The tree is built by considering the taxonomic lineage of each sequence that has a match to this family. For each node in the resulting tree, we draw an arc in the sunburst. The radius of the arc, its distance from the root node at the centre of the sunburst, shows the taxonomic level ("superkingdom", "kingdom", etc). The length of the arc represents either the number of sequences represented at a given level, or the number of species that are found beneath the node in the tree. The weighting scheme can be changed using the sunburst controls.
In order to reduce the complexity of the representation, we reduce the number of taxonomic levels that we show. We consider only the following eight major taxonomic levels:
Colouring and labels
Segments of the tree are coloured approximately according to their superkingdom. For example, archeal branches are coloured with shades of orange, eukaryotes in shades of purple, etc. The colour assignments are shown under the sunburst controls. Where space allows, the name of the taxonomic level will be written on the arc itself.
As you move your mouse across the sunburst, the current node will be highlighted. In the top section of the controls panel we show a summary of the lineage of the currently highlighed node. If you pause over an arc, a tooltip will be shown, giving the name of the taxonomic level in the title and a summary of the number of sequences and species below that node in the tree.
Anomalies in the taxonomy tree
There are some situations that the sunburst tree cannot easily handle and for which we have work-arounds in place.
Missing taxonomic levels
Some species in the taxonomic tree may not have one or more of the main eight levels that we display. For example, Bos taurus is not assigned an order in the NCBI taxonomic tree. In such cases we mark the omitted level with, for example, "No order", in both the tooltip and the lineage summary.
Unmapped species names
The tree is built by looking at each sequence in the full alignment for the family. We take the name of the species given by UniProt and try to map that to the full taxonomic tree from NCBI. In some cases, the name chosen by UniProt does not map to any node in the NCBI tree, perhaps because the chosen name is listed as a synonym or a misspelling in the NCBI taxonomy.
So that these nodes are not simply omitted from the sunburst tree, we group them together in a separate branch (or segment of the sunburst tree). Since we cannot determine the lineage for these unmapped species, we show all levels between the superkingdom and the species as "uncategorised".
Since we reduce the species tree to only the eight main taxonomic levels, sequences that are mapped to the sub-species level in the tree would not normally be shown. Rather than leave out these species, we map them instead to their parent species. So, for example, for sequences belonging to one of the Vibrio cholerae sub-species in the NCBI taxonomy, we show them instead as belonging to the species Vibrio cholerae.
Too many species/sequences
For large species trees, you may see blank regions in the outer layers of the sunburst. These occur when there are large numbers of arcs to be drawn in a small space. If an arc is less than approximately one pixel wide, it will not be drawn and the space will be left blank. You may still be able to get some information about the species in that region by moving your mouse across the area, but since each arc will be very small, it will be difficult to accurately locate a particular species.
The tree shows the occurrence of this domain across different species. More...
We show the species tree in one of two ways. For smaller trees we try to show an interactive representation, which allows you to select specific nodes in the tree and view them as an alignment or as a set of Pfam domain graphics.
Unfortunately we have found that there are problems viewing the interactive tree when the it becomes larger than a certain limit. Furthermore, we have found that Internet Explorer can become unresponsive when viewing some trees, regardless of their size. We therefore show a text representation of the species tree when the size is above a certain limit or if you are using Internet Explorer to view the site.
If you are using IE you can still load the interactive tree by clicking the "Generate interactive tree" button, but please be aware of the potential problems that the interactive species tree can cause.
For all of the domain matches in a full alignment, we count the number that are found on all sequences in the alignment. This total is shown in the purple box.
We also count the number of unique sequences on which each domain is found, which is shown in green. Note that a domain may appear multiple times on the same sequence, leading to the difference between these two numbers.
Finally, we group sequences from the same organism according to the NCBI code that is assigned by UniProt, allowing us to count the number of distinct sequences on which the domain is found. This value is shown in the pink boxes.
We use the NCBI species tree to group organisms according to their taxonomy and this forms the structure of the displayed tree. Note that in some cases the trees are too large (have too many nodes) to allow us to build an interactive tree, but in most cases you can still view the tree in a plain text, non-interactive representation. Those species which are represented in the seed alignment for this domain are highlighted.
You can use the tree controls to manipulate how the interactive tree is displayed:
- show/hide the summary boxes
- highlight species that are represented in the seed alignment
- expand/collapse the tree or expand it to a given depth
- select a sub-tree or a set of species within the tree and view them graphically or as an alignment
- save a plain text representation of the tree
Please note: for large trees this can take some time. While the tree is loading, you can safely switch away from this tab but if you browse away from the family page entirely, the tree will not be loaded.
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 N6_N4_Mtase domain has been found. There are 16 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.
Loading structure mapping...