II-Q restriction endonucleases--new class of type II enzymes.

Unique restriction endonucleases Bpu 10l and Bsil have been isolated from Bacillus pumilas and Bacillus sphaericus, respectively. The recognition sequences and cleavage points of these enzymes have been determinated as 5'-CC1TNAGC-3'/3'-GGANT1CG-5' for Bpu 10l and 5'-C1TCGTG-3'/3'-GAGCA1C-5' for Bsil. Restriction endonucleases Bpu 10l and Bsil represent a new class of enzymes which recognize non-palindromic nucleotide sequences and hydrolize DNA within the recognition sequence. Bpu 10l and Bsil recognition sequences may be regarded as quasipalindromic and the enzymes may be designated as type II-Q restriction endonucleases.