Abstract
We report the characterization and cloning of the genes for an unusual type IV restriction-modification system, BspLU11III, from Bacillus sp. LU11. The system consists of two methyltransferases and one endonuclease, which also possesses methyltransferase activity. The three genes of the restriction-modification system, bsplu11IIIMa, bsplu11IIIMb and bsplu11IIIR, are closely linked and tandemly arranged. The corresponding enzymes recognize the dsDNA sequence 5'-GGGAC-3'/5'-GTCCC-3', with M.BspLU11IIIa modifying the A (underlined) of one strand and M.BspLU11IIIb the inner C (underlined) of the other strand. R.BspLU11III has both endonuclease and adenine-specific methyltransferase activities and is able to protect the DNA against cleavage by itself. In contrast to all type IV restriction-modification systems described so far, which have only one adenine-specific methyltransferase, BspLU11III is the first type IV restriction-modification system that includes two methyltransferases, one of them being cytosine specific.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Bacillus / enzymology
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Bacillus / genetics*
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Base Sequence
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Binding Sites / genetics
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Cloning, Molecular
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DNA Methylation
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DNA Restriction-Modification Enzymes / genetics*
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DNA Restriction-Modification Enzymes / metabolism
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DNA, Bacterial / chemistry
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DNA, Bacterial / genetics
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DNA, Bacterial / metabolism
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DNA-Cytosine Methylases / genetics*
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DNA-Cytosine Methylases / metabolism
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Deoxyribonucleases, Type II Site-Specific / genetics*
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Deoxyribonucleases, Type II Site-Specific / metabolism
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Escherichia coli / genetics
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Gene Expression
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Molecular Sequence Data
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Sequence Alignment
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Sequence Analysis, DNA
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Sequence Homology, Amino Acid
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Site-Specific DNA-Methyltransferase (Adenine-Specific) / genetics*
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Site-Specific DNA-Methyltransferase (Adenine-Specific) / metabolism
Substances
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DNA Restriction-Modification Enzymes
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DNA, Bacterial
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DNA-Cytosine Methylases
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Site-Specific DNA-Methyltransferase (Adenine-Specific)
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endodeoxyribonuclease BspLU11I
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Deoxyribonucleases, Type II Site-Specific