Open AccessA type II restriction endonuclease of Streptococcus thermophilus ST117
Author(s) -
Solaiman Daniel K.Y.,
Somkuti George A.
Publication year - 1991
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1991.tb04639.x
Subject(s) - isoschizomer , restriction enzyme , endonuclease , size exclusion chromatography , enzyme , chemistry , chromatography , incubation , cleavage (geology) , dna , biochemistry , microbiology and biotechnology , biology , paleontology , gene expression , fracture (geology) , dna methylation , gene
Summary Streptococcus thermophilus strain 117 produces a type II restriction endonuclease designated as Sth 117I. This enzyme was isolated from cell extracts by membrane filtration and ammonium sulfate fractionation. Anion exchange chromatography on a DE52 column yielded an enzyme preparation free of nonspecific nucleases. The optimal reaction conditions for Sth 117I are: (1) [MgCl 2 ] le; 5 mM; (2) pH range of 6.5–7; (3) incubation temperature between 37 and 50°C; and (4) [NaCl] or [KCl] ≥ 50 mM. The results of single‐ and double‐digestion experiments indicated that the Sth 117I was an isoschizomer of Bst NI and Eco RII with the recognition sequence of 5′‐CCWGG‐3′. The cleavage site of Sth 117I was identified as 5′‐CCWGG‐3′ by 5′‐end analysis. This was supported by the results of ligation experiments with Sth 117I‐restricted DNAs and the Bst NI‐ or Eco RII‐generated fragments.