Modern Industrial Microbiology and Biotechnology

140 Modern Industrial Microbiology and BiotechnologyTable 7.4Restriction EndonucleasesA: Patterns of Endonucleases Cutting);B: Some Restriction Endoncleases and their Recognition SequencesThe same restriction endonuclease is used to cut the foreign DNA to be inserted into avector, as well as the vector itself, in order to open it up.Restriction enzymes cut DNA between deoxyribose and phosphate groups, leaving aphosphate at 5’ end and an OH group at the 3’. The restriction enzymes used in geneticengineering cut within their recognition sites and generate one of three types of ends (seeTable 74.4A):a) Single-stranded, “sticky” or cohesive ends as cut by Bam H1 (1, 5’ overhangs).b) Single-stranded, “sticky” or cohesive ends as cut by Kpn 1 (2, 3’ overhangs).c) Double-stranded, “blunt” ends as cut by Sma 1. (3, Blunts)