ABSTRACT
The preparation of site-specific endonuclease Bsp123 I was isolated and purified from the thermophilic strain Bacillus species 123. Endonuclease Bsp123 I recognizes the sequence CGCG and cleaves it in the middle between nucleotides G and C, producing blunt ends. Thus, Bsp123 I is an isoschizomer of FnuDII. The maximal activity of the enzyme is displayed at 42 degrees C, pH 8.0, 100 mM NaCl, 10 mM MgCl2.
Subject(s)
Bacillus/enzymology , Deoxyribonucleases, Type II Site-Specific/isolation & purification , DNA, Viral/metabolism , Deoxyribonucleases, Type II Site-Specific/metabolism , Substrate SpecificityABSTRACT
Thermophilic strain Bacillus species AA contains several site-specific endonucleases and three of them have been identified. BspAAI recognizes the sequence 5'-C downward arrow TCGAG-3' and cleaves it after the first "C" forming 4-nucleotide 5'-ends and is an isoschizomer of XhoI. BspAAII recognizes the sequence 5'-T downward arrow CTAGA-3' and cleaves it after the first "T" forming 4-nucleotide 5'-ends and is an isoschizomer of XbaI. BspAAIII recognizes the sequence 5'-GGATCC-3' and is an isomer of BamHI. The optimal temperature and pH values are 42-48 degreesC and 7.0-8.0, respectively.
