SITE-SPECIFIC RESTRICTION ENDONUCLEASES IN BACILLUS-LICHENIFORMIS

We systematically studied site-specific restriction endonucleases in Bacillus licheniformis strains and detected endonuclease activity in 25 of 217 strains tested. Three different activities were obtained. One of these activities detected in 21 strains was the most representative within the species and produced a banding pattern, after digestion of A DNA, identical to that seen with ClaI. Two other strains isolated from soil samples from China and USA were found to produce a DNA-cleaving enzyme with the same recognition sequence as BsaI. One producer strain, isolated from a Peruvian soil sample, showed to possess a mixture of two isoschizomers, ClaI and BsaI. Finally, one strain produced an endonuclease activity, not previously described in B. licheniformis, that showed the same recognition sites as Bsu361.