Summary: MmeI, DNA-methyltransferase domain
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MmeI, DNA-methyltransferase domain Provide feedback
Type IIL Restriction-Modification Enzyme MmeI is a large enzyme that integrates DNA recognition and methyltransferase and endonuclease activities within the same polypeptide [2, 3, 4]. MmeI is composed of five domains. An N-terminal endonuclease domain (residues 1-155), connects to a DNA-methyltransferase domain (MTase, residues 301-320) via a multi-helical spacer (residues 156-300). These are followed by the target recognition domain (TRD, residues 621-825), and a final C-terminal helical bundle (residues 826-919) . The DNA is embedded between the TRD and the MTase domain. The TRD makes contacts to the DNA bases primarily in the major groove, while the MTase domain makes several contacts to the DNA in the minor groove . This domain corresponds to the DNA-methyltransferase. Structurally, it consists of a twisted beta-sheet flanked by alpha-helices on both sides.
Callahan SJ, Luyten YA, Gupta YK, Wilson GG, Roberts RJ, Morgan RD, Aggarwal AK;, PLoS Biol. 2016;14:e1002442.: Structure of Type IIL Restriction-Modification Enzyme MmeI in Complex with DNA Has Implications for Engineering New Specificities. PUBMED:27082731 EPMC:27082731
Morgan RD, Bhatia TK, Lovasco L, Davis TB;, Nucleic Acids Res. 2008;36:6558-6570.: MmeI: a minimal Type II restriction-modification system that only modifies one DNA strand for host protection. PUBMED:18931376 EPMC:18931376
Boyd AC, Charles IG, Keyte JW, Brammar WJ;, Nucleic Acids Res. 1986;14:5255-5274.: Isolation and computer-aided characterization of MmeI, a type II restriction endonuclease from Methylophilus methylotrophus. PUBMED:3016643 EPMC:3016643
Tucholski J, Zmijewski JW, Podhajska AJ;, Gene. 1998;223:293-302.: Two intertwined methylation activities of the MmeI restriction-modification class-IIS system from Methylophilus methylotrophus. PUBMED:9858752 EPMC:9858752
Park SY, Lee HJ, Song JM, Sun J, Hwang HJ, Nishi K, Kim JS;, Acta Crystallogr D Biol Crystallogr. 2012;68:1570-1577.: Structural characterization of a modification subunit of a putative type I restriction enzyme from Vibrio vulnificus YJ016. PUBMED:23090406 EPMC:23090406
Liu YP, Tang Q, Zhang JZ, Tian LF, Gao P, Yan XX;, Proc Natl Acad Sci U S A. 2017;114:11151-11156.: Structural basis underlying complex assembly and conformational transition of the type I R-M system. PUBMED:28973912 EPMC:28973912
Internal database links
|SCOOP:||Eco57I Methyltransf_31 MTS N6_Mtase UPF0020|
|Similarity to PfamA using HHSearch:||UPF0020 N6_Mtase|
This tab holds annotation information from the InterPro database.
No InterPro data for this Pfam family.
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:
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This family is a member of clan NADP_Rossmann (CL0063), which has the following description:
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 209 members:2-Hacid_dh_C 3Beta_HSD 3HCDH_N 3HCDH_RFF 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 BMT5-like BpsA_C CARME CbiJ CheR CMAS CmcI CoA_binding CoA_binding_2 CoA_binding_3 Cons_hypoth95 CoV_ExoN CoV_Methyltr_2 DAO DapB_N DFP DNA_methylase DOT1 DRE2_N DREV DUF1442 DUF1611_N DUF166 DUF1776 DUF268 DUF2855 DUF3410 DUF364 DUF5129 DUF5130 DUF6094 DUF938 DXP_reductoisom DXPR_C 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 fvmX7 G6PD_N GCD14 GDI GDP_Man_Dehyd GFO_IDH_MocA GIDA GidB GLF Glu_dehyd_C Glyco_hydro_4 Glyco_tran_WecG GMC_oxred_N Gp_dh_N GRAS GRDA HcgC HI0933_like HIM1 IlvN ISPD_C KR LCM Ldh_1_N LpxI_N Lycopene_cycl Lys_Orn_oxgnase Malic_M Mannitol_dh MCRA Met_10 Methyltr_RsmB-F Methyltr_RsmF_N Methyltrans_Mon Methyltrans_SAM Methyltransf_10 Methyltransf_11 Methyltransf_12 Methyltransf_14 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_33 Methyltransf_34 Methyltransf_4 Methyltransf_5 Methyltransf_7 Methyltransf_8 Methyltransf_9 Methyltransf_PK MethyltransfD12 MetW Mg-por_mtran_C MmeI_Mtase MOLO1 Mqo MT-A70 MTS Mur_ligase 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 OCD_Mu_crystall OpcA_G6PD_assem Orbi_VP4 PALP PARP_regulatory PCMT PDH_N PglD_N Polysacc_syn_2C Polysacc_synt_2 Pox_MCEL Pox_mRNA-cap Prenylcys_lyase PrmA PRMT5 Pyr_redox Pyr_redox_2 Pyr_redox_3 Reovirus_L2 RmlD_sub_bind Rossmann-like rRNA_methylase RrnaAD Rsm22 RsmJ Sacchrp_dh_NADP SAM_MT SE Semialdhyde_dh Shikimate_DH Spermine_synth SRR1 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 Urocanase 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 and the UniProtKB 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
You can see the alignments as HTML or in three different sequence viewers:
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You can download (or view in your browser) a text representation of a Pfam alignment in various formats:
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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.
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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...
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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.
This family is new in this Pfam release.
|Seed source:||MGnify-UniProt clustering|
|Number in seed:||160|
|Number in full:||2704|
|Average length of the domain:||199.2 aa|
|Average identity of full alignment:||20 %|
|Average coverage of the sequence by the domain:||19.71 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||1|
|Download:||download the raw HMM for this family|
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This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. 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:
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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.
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 MmeI_Mtase 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 sequence.
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AlphaFold Structure Predictions
The list of proteins below match this family and have AlphaFold predicted structures. Click on the protein accession to view the predicted structure.
|Protein||Predicted structure||External Information|
|O26046||View 3D Structure||Click here|
|O31504||View 3D Structure||Click here|
|Q0PC94||View 3D Structure||Click here|
|Q60301||View 3D Structure||Click here|
|Q8CJM2||View 3D Structure||Click here|
|Q8ZK12||View 3D Structure||Click here|