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| A novel site-specific endonuclease GluI recognizes methylated DNA sequence 5-G(5mC)^NG(5mC)-3/3-(5mC)GN^(5mC)G. |
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| | A novel site-specific endonuclease GluI from the bacterial strain GL24 has been isolated and characterized. The enzyme recognizes methylated DNA sequence 5-G(5mC)^NG(5mC)-3/3-(5mC)GN^(5mC)G-5 and cleaves it as it is shown by arrow. Due to its ability to cleave only modified DNA GluI may be useful for genetic engineering experiments as well as for determination of DNA methylation status in eucaryotes. | |
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| Site-specific endonuclease BlsI recognizes DNA sequence 5-G(5mC)N^GC-3 and cleaves it producing 3 sticky ends |
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| | A bacterial strain Bacillus simplex 23, a producer of a site-specific endonuclease BlsI has been discovered. BlsI recognizes the methylated DNA sequence 5-G(5mC)N↓GC-3, like the earlier described site-specific endonuclease BisI (recognition site 5-G(5mC)↓NGC-3), but differs in positions of DNA cleavage producing 3-protruding ends. Due to its ability to cleave only methylated DNA, enzyme BlsI can find an application in gene engineering works as well as in determining the methylation status of eucaryotic DNA. | |
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| New Restriction Endonuclease AluBI from Arthrobacter luteus B - AluI Isoshizomer, nonsensitive to Presence of 5-methylcytosine in the Recognition Sequence AGCT |
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| | A new restriction endonuclease AluBI has been discovered and characterized. AluBI is an isoshizomer of well known restriction endonuclease AluI, which recognizes DNA sequence AGCT. Unlike AluI, enzyme AluBI is able to cleave DNA when recognition sequence contains 5-methylcytosines. AluBI also cleaves recognition sequence with two methylated cytosines, one modified at N4 and other at C5 positions. However, new enzyme doesnt cleave DNA with two N4-methylcytosines in the recognition site. | |
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| A novel restriction endonuclease GlaI recognizes methylated sequence 5-G(m5C)^GC-3 |
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| | A novel restriction endonuclease GlaI from the bacterial strain GL29 has been isolated and characterized. The enzyme recognizes methylated DNA sequence 5-G(5mC)↓GC-3 and cleaves it as indicated by arrow. Due to its ability to cleave only modified DNA GlaI may find a practical application in genetic engineering experiments as well as in determination of DNA methylation status. | |
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| New Eight Bases Cutter AbsI from Arthrobacter species Recognizes Palindromic DNA Sequence 5-CC^TCGAGG-3 |
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| | Bacterial strain Arthrobacter species7M06 producing site-specific endonuclease AbsI has been discovered. AbsI recognizes palindromic octanucleotide DNA sequence 5-CC^TCGAGG-3 and hydrolyzes it after second cytosine, producing 5- sticky ends, which are compatible with sticky ends after DNA cleavage by restriction endonucleases XhoI (5-C^TCGAG-3), PspXI (5-VC^TCGAGB-3) and SalI (5-G^TCGAC-3). Among all known rare-cutting site-specific endonucleases AbsI is the only enzyme which has no recognition sequences in standard substrates Lambda and T7 DNAs and Adenovirus type 2 DNA | |
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| PspXI, a novel restriction endonuclease that recognizes the unusual DNA sequence 5-VC↓TCGAGB-3 |
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| | We have discovered a bacterial strain Pseudomonas species X11 that produces the unique restriction endonuclease PspXI. This enzyme recognizes the degenerate octanucleotide sequence 5-VCTCGAGB-3, where V stands for A, C or G and B stands for T, C or G.
The PspXI restriction endonuclease preparation with the specific activity of 10000 units/ml was isolated using four chromatographic steps. PspXI cuts its recognition sequence between C and T producing cohesive ends compatible with those of produced by XhoI and SalI restriction endonucleases.
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| Restriction endonuclease Bis I from Bacillus subtilis T30 recognizes methylated sequence 5-G(m5C)↓NGC-3 |
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| | Bacillus subtilis strain T30, producing a novel restriction endonuclease Bis I, has been isolated and characterized. The enzyme recognizes methylated DNA sequence 5-G(5mC)↓NGC-3 and cleaves it as it is shown by arrow. Due to cleavage of only modified DNAs Bis I may find a practical application in genetic engineering experiments as well as in determination of eukaryotic DNA methylation status. | |
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| Restriction Endonuclease AjnI from Acinetobacter johnsonii R2, an Isoschizomer of EcoRII, recognizes 5'- CCWGG-3' and cleaves dcm-methylated sites |
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| | A producer of restriction endonuclease AjnI has been isolated from natural resources and identified as bacterial species Acinetobacter johnsonii R2. The restriction enzyme purification and estimation of its activity is described. It has been shown that AjnI produces DNA fragments with 5'-CCWGG sticky ends similar to EcoRII, but cleavage is not blocked by dcm-methylation. A new restriction endonuclease AjnI may be widely used in genetic engineering. | |
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| A new site-specific DNA nickase N.Bst9I from Bacillus stearothermophilus 9 |
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| | Bacillus stearothermophilus 9 strain has been found during screening of
bacteria from natural sources which produces a new site-specific nickase
N.Bst9I. This enzyme recognizes and cleaves nucleotide sequence 5'-GAGTCNNNN^-3',
so it is an isoschizomer of N.BstSEI endonuclease found earlier. But enzymatic
properties of both enzymes are considerably different. N.Bst9I application in
genetic engineering and biotechnology is more preferable because its "star"
activity is much lower in comparison to N.BstSEI.
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| BtrI, a novel restriction endonuclease, recognises the non-palindromic sequence 5'-CACGTC(-3/-3)-3' |
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| | The recognition sequence and cleavage positions of a new restriction endonuclease BtrI isolated from Bacillus stearothermophilus SE-U62 have been determined. BtrI belongs to a rare type IIQ of restriction endonucleases, which recognise non-palindromic nucleotide sequences and cleave DNA symmetrically within them.
Type II restriction endonucleases (ENases) include a group of 53 prototypes that recognise non-palindromic DNA sequences (ENases with recognition sequences that are interrupted by more than one base pair are not considered). Cleavage positions have been determined for 45 of these [1]. Mainly, such ENases cleave DNA outside their recognition sites and are designated type IIS [2]. There are only a few so-called type IIQ restriction enzyme prototypes that cut both DNA strands symmetrically within their non-palindromic recognition sequences [3].
Here we report a new member of this rare subgroup of type II ENases.
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| PsiI, a unique Restriction Endonuclease Recognizing the DNA Sequence 5'-TTA^TAA-3' |
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| | PsiI, a new restriction endonuclease produced by the bacterial strain Pseudomonas sp. SE-G49, has been isolated and characterized. The enzyme cleaves DNA in the middle of its palindromic recognition sequence 5-TTA^TAA-3'. Thus, PsiI belongs to a rare group of type II restriction endonucleases whose recognition sites consist of AT base pairs only. | |
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| AccBSI: A New Restriction Endonuclease from Acinetobacter calcoaceticus BS |
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| | The recognition site of a new restriction endonuclease from Acinetobacter calcoaceticus BS was determined. This is a nonpalindromic sequence
5'-GAGCGG-3'
3'-CTCGCC-5'
AccBSI restriction endonuclease cleaves DNA chains in the middle of the recognition sequence; therefore, ligation of its digestion fragments restores AccBSI recognition sites and generates palindromic sequences recognized by SacI and SacII restriction endonucleases. | |
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| N.BstSE, Site-Specific Nickase from Bacillus stearothermophilus SE-589 |
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| | A site-specific nickase recognizing and cleaving the DNA site
5'-G-A-G-T-C-N-N-N-N^N-N-3'
3'-C-T-C-A-G-N-N-N-N-N-N-5'
was isolated from Bacillus stearothermophilus SE-589 and named N.BstSE. Its properties indicate a possible relation with type II restriction endonucleases.
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