[Interaction of BamH1 restrictase with synthetic substrates containing complete or partial recognition sites of this enzyme].

BamHI restriction patterns of the self-complementary oligodeoxyribonucleotides were investigated. Cleavage of the oligonucleotides, containing full-length recognition site GGATCC. shows a usual type of restriction pattern. The oligonucleotide d(5'-TCCAGATCTGGA) contains part of the recognition sequences 5'-GATC flanked with the half-size recognition sequences 5'-TCC from its 5'-side and 5'-GGA from its 3'-side. Cleavage of this substrate shows a restriction pattern which could be explained as being cleaved within the recognition sequence d(5'-GGA...TCC) formed by the ends of two substrate molecules. At the same time cleavage within the sequence d(5'-GATC) does not take place. These results support a symmetric binding model of a restriction nuclease with its recognition site via interaction with one half of the recognition sequence.