Summary: TaqI restriction endonuclease
TaqI restriction endonuclease Provide feedback
This family includes the TaqI (recognises and cleaves T^CGA) restriction endonuclease.
Liang X, Jensen K, Frank-Kamenetskii MD; , Biochemistry. 2004;43:13459-13466.: Very efficient template/primer-independent DNA synthesis by thermophilic DNA polymerase in the presence of a thermophilic restriction endonuclease. PUBMED:15491153 EPMC:15491153
Steczkiewicz K, Muszewska A, Knizewski L, Rychlewski L, Ginalski K;, Nucleic Acids Res. 2012;40:7016-7045.: Sequence, structure and functional diversity of PD-(D/E)XK phosphodiesterase superfamily. PUBMED:22638584 EPMC:22638584
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR019073
There are four classes of restriction endonucleases: types I, II,III and IV. All types of enzymes recognise specific short DNA sequences and carry out the endonucleolytic cleavage of DNA to give specific double-stranded fragments with terminal 5'-phosphates. They differ in their recognition sequence, subunit composition, cleavage position, and cofactor requirements [PUBMED:15121719, PUBMED:12665693], as summarised below:
- Type I enzymes (EC) cleave at sites remote from recognition site; require both ATP and S-adenosyl-L-methionine to function; multifunctional protein with both restriction and methylase (EC) activities.
- Type II enzymes (EC) cleave within or at short specific distances from recognition site; most require magnesium; single function (restriction) enzymes independent of methylase.
- Type III enzymes (EC) cleave at sites a short distance from recognition site; require ATP (but doesn't hydrolyse it); S-adenosyl-L-methionine stimulates reaction but is not required; exists as part of a complex with a modification methylase methylase (EC).
- Type IV enzymes target methylated DNA.
Type II restriction endonucleases (EC) are components of prokaryotic DNA restriction-modification mechanisms that protect the organism against invading foreign DNA. These site-specific deoxyribonucleases catalyse the endonucleolytic cleavage of DNA to give specific double-stranded fragments with terminal 5'-phosphates. Of the 3000 restriction endonucleases that have been characterised, most are homodimeric or tetrameric enzymes that cleave target DNA at sequence-specific sites close to the recognition site. For homodimeric enzymes, the recognition site is usually a palindromic sequence 4-8 bp in length. Most enzymes require magnesium ions as a cofactor for catalysis. Although they can vary in their mode of recognition, many restriction endonucleases share a similar structural core comprising four beta-strands and one alpha-helix, as well as a similar mechanism of cleavage, suggesting a common ancestral origin [PUBMED:15770420]. However, there is still considerable diversity amongst restriction endonucleases [PUBMED:14576294, PUBMED:11827971]. The target site recognition process triggers large conformational changes of the enzyme and the target DNA, leading to the activation of the catalytic centres. Like other DNA binding proteins, restriction enzymes are capable of non-specific DNA binding as well, which is the prerequisite for efficient target site location by facilitated diffusion. Non-specific binding usually does not involve interactions with the bases but only with the DNA backbone [PUBMED:11557805].
This entry represents the restriction endonuclease TaqI, which recognises and cleaves the double-stranded sequence T^CGA.
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)|
|Type II site-specific deoxyribonuclease activity (GO:0009036)|
|Biological process||DNA restriction-modification system (GO:0009307)|
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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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Curation and family details
|Seed source:||Bateman A|
|Number in seed:||4|
|Number in full:||13|
|Average length of the domain:||199.50 aa|
|Average identity of full alignment:||46 %|
|Average coverage of the sequence by the domain:||95.09 %|
|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:||5|
|Download:||download the raw HMM for this family|
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