Open AccessBst B7SI (R↓CCGGY), a thermostable isoschizomer of Cfr 10I, from a strain of Bacillus stearothermophilus isolated from oil‐contaminated soil in Kuwait
Author(s) -
AlAwadhi Sameera,
Welch Simon G.,
Smith Kelvin E.,
Williams Ralph A.D.
Publication year - 1998
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.1574-6968.1998.tb12912.x
Subject(s) - isoschizomer , bacillus pumilus , thermophile , restriction enzyme , endonuclease , mesophile , bacillaceae , strain (injury) , dna , bacillus (shape) , biology , enzyme , bacteria , phosphodiester bond , ecori , bacillales , microbiology and biotechnology , recognition sequence , biochemistry , rna , genetics , gene expression , anatomy , bacillus subtilis , gene , dna methylation
Isolates of thermophilic bacteria from desert soil in Kuwait, heavily contaminated with crude oil, have been screened for the presence of restriction endonuclease activity. One of the isolates (B7S), identified as Bacillus stearothermophilus , showed a high level of restriction endonuclease activity when a cell‐free extract was incubated with λ bacteriophage DNA at 65°C. A type II restriction endonuclease ( Bst B7SI) has been partially purified from this isolate. Bst B7SI recognises the six‐base sequence RCCGGY (R=A or G; Y=T or C) and hydrolyses the phosphodiester bond in both strands of the DNA substrate between the first and second bases of the recognition sequence 5′‐R↓CCGGY‐3′ producing four‐base 5′ overhangs. Bst B7SI is therefore an isoschizomer of the mesophilic prototype restriction endonuclease Cfr 10I. Bst B7SI has a pH optimum of 9.7, requires 10 mM MgCl 2 and 75 mM NaCl for maximum activity, and retains full enzyme activity when incubated for 5 min at temperatures up to 70°C.