SRUI RESTRICTION-ENDONUCLEASE FROM SELENOMONAS-RUMINANTIUM

SruI, specific restriction endonuclease, has been characterized from S elenomonas ruminantium isolated from the rumen of fallow deer. Results from the study demonstrate that S. ruminantium 18D possesses a type I I restriction endonuclease, which recognizes the sequence 5'-TTT down AAA-3'. The recognition sequence of SruI was identified using digestio ns on pBR322, pBR328, pUC18, M13mp18RF, pACYC184 and lambdaDNA. The cl eavage patterns obtained were compared with computer-derived data. Sru I recognises the palindromic hexanucleotide sequence and cleaves DNA a fter the third T in the sequence, producing blunt ends. The purificati on and characterization of restriction endonuclease SruI presented her e is the first described for Selenomonas ruminantium spp. and demonstr ates that this microorganism possesses a DNA-cleaving enzyme with the same specificity as DraI or AhaIII.