3.1.21.3: type I site-specific deoxyribonuclease
This is an abbreviated version!
For detailed information about type I site-specific deoxyribonuclease, go to the full flat file.
Word Map on EC 3.1.21.3
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3.1.21.3
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methyltransferase
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methylase
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phage
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endonucleases
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mtases
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bacteriophage
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duplex
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unmethylated
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isoschizomer
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prophage
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exonuclease
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dna-methyltransferase
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enase
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recbcd
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n6-adenine
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ssoii
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hemimethylated
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clpxp
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n6-methyladenine
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biotechnology
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medicine
- 3.1.21.3
- methyltransferase
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methylase
- phage
- endonucleases
- mtases
- bacteriophage
- duplex
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unmethylated
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isoschizomer
- prophage
-
exonuclease
- dna-methyltransferase
-
enase
-
recbcd
-
n6-adenine
- ssoii
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hemimethylated
- clpxp
- n6-methyladenine
- biotechnology
- medicine
Reaction
endonucleolytic cleavage of DNA to give random double-stranded fragments with terminal 5'-phosphates; ATP is simultaneously hydrolysed =
Synonyms
adenosine triphosphate-dependent deoxyribonuclease, ATP-dependent deoxyribonuclease, ATP-dependent DNase, BsaHI restriction-modification system, C.PvuII, CfrAI, deoxyribonuclease (ATP- and S-adenosyl-L-methionine dependent), deoxyribonuclease (ATP-dependent), DNase, EC 3.1.23, EC 3.1.24, EC 3.1.4.33, Eco377I, Eco394I, Eco585I, Eco646I, Eco777I, Eco826I, Eco851I, Eco912I, EcoA0ORF42P, EcoAI, EcoAO83I, EcoB, EcoBI, EcoDI, EcoDXXI, EcoEI, EcoGIV, EcoK, EcoKI, EcoKI type I DNA restriction enzyme, EcoKI type I restriction-modification system, EcoprrI, EcoR, EcoR124, EcoR124/3I, EcoR124I, EcoR124II, EcoRII modification enzyme, EcoRII RM gene complex, EcoRII system, endodeoxyribonuclease, Esp1396I, exodeoxyribonuclease, H91_orf206, H91_orf376, HpyAXII restriction-modification system, HsdM, HsdR, hsdS, KpnBI, More, MpnORFDAP, MpnORFDBP, nuclease, deoxyribo-, nuclease, deoxyribo-, ATP-dependent, PspGI endonuclease, PspGI restriction-modification system, R. BsaHI, R.EcoAI, R.EcoEI, R.EcoKI, R.EcoR124I restriction endonuclease, R.EcoR124II, R.EcoR124INT, R.HpyAXII, R.PspGI, REase, RecoK, restriction-modification system, Sau1, Sau1 type I restriction-modification system, Sau1 Type I RM system, SauMW2I, SauMW2II, SauN315I, SauN315II, StyLTIII, StySBI, StySEAI, StySGI, StySJI, StySKI, StySPI, StySQI, type I R-M enzyme, type I R-M system, type I restriction enzyme, type I restriction modification enzyme, type I restriction-modification enzyme, type I restriction-modification system, type I restriction-modification system EcoR124I, type IB restriction enzyme, type II R-M system, type II restriction-modification system
ECTree
3.1.21.3 type I site-specific deoxyribonucleaseAdvanced search results
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Engineering on EC 3.1.21.3 - type I site-specific deoxyribonuclease
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PROTEIN VARIANTS 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
K220A
the mutant enzyme shows a 5fold reduction in restriction activity. The mutant motor subunit is not defective in interacting with the methyltransferase to form the endonuclease complex
K220Q
the mutant enzyme shows a 400fold reduction in restriction activity. The mutant motor subunit is not defective in interacting with the methyltransferase to form the endonuclease complex
K220R
the mutant motor subunit is not defective in interacting with the methyltransferase to form the endonuclease complex
L80P
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L80P mutation in the modification enzyme of the EcoRII gene complex confers thermosensitivity of cell growth (shows activity at 30°C but not at 37°C). Under a condition of inhibited protein synthesis, the activity of the mutant is completely lost at a high temperature. In parallel, the L80P mutant protein disappears more rapidly than the wild-type protein
T239C
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shows decreased DNA methyltransferase activity at a higher temperature in vivo and in vitro than the nonmutated enzyme
additional information
additional information
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a temperature-sensitive mutation within the hsdS gene appears to affect the ability of the HsdR subunit to interact with the HsdS subunit when forming an active endonuclease
additional information
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mutation in which the specificity has altered due to a Tn5 insertion into the middle of the hsdS, the gene which encodes the polypeptide that confers DNA sequence specificity to both the restriction and the modification reaction. The mutant recognition sequence is an interrupted palindrome, TCA(N8)TGA, in which the 5' half site of the wild type site is repeated in inverse orientation. The additional base pair in the non-specific spacer of the mutant recognition sequence maintains the proper spacing between the two methylatable adenine groups. Tn5 insertion occurs at nucleotide 673 of the 1221 bp gene. This effectively deletes the entire carboxyl-terminal DNA binding domain which recognizes the 3' half of the EcoDXXI binding site. The truncated hsdS gene still encodes both the amino-terminal DNA binding domain and the conserved repeated sequence that defines the length of the recognition site spacer region
additional information
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N-terminal 83-amino-acid deletion mutant, shows activity at at 30°C and 37°C. The EcoRII RM gene complex is a mutant carrying a T239C (L80P) substitution in the modification gene and a synonymous T402C substitution in the restriction gene. The capability of the restriction-modification system EcoRII in forcing maintenance on its host can be modulated by a region of its antitoxin, the modification enzyme, as in the classical postsegregational killing systems
additional information
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point mutation within the hsdS gene or insertional mutagenesis using the Tn5 transposon, both show new DNA specificities. Both new specificities are due to the production of a truncated HsdS subunit, which is able to dimerize, producing the recognition sequence GAAn7TTC in the case of the point mutation of EcoR124I, which produces a stop codon and hence the truncated subunit
additional information
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gene of subunit hsdR from strain RN4220 contains a premature stop codon resulting in a truncated R.Sau1 product of 192 amino acids. Strain RN4220 can accept plasmid DNA from Escherichia coli. The truncated hsdR subunit is responsible for this phenotype and its complementation restores a nontransformable phenotype. Complemented strain RN4220 is resisitant to bacteriophage lysis if the phage is grown on staphylococcus aureus of a different lineage
additional information
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hsdR null mutants, complete deletion of the hsdR gene is not sufficient to generate readily transformable NCTC8325-4, SH1000 and COL strains. HsdR mutant strains have growth rates identical to the parental strains and and are competent if transformed with appropriately modified Staphylococcus aureus DNA. HsdR mutants are competent but do not accept foreign DNA due to the presence of additional factor(s) that degrade unmodified DNA. Heat treatment of competent cells increases transformation efficiency of hsdR mutants
additional information
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mutations within the tetranucleotide repeats diminish binding of C.Esp1396I. Insertion of an additional base into the TATA sequence to make the GACT/AGCT sequences symmetric around a TAT spacer reduces DNA binding
