Open AccessRestriction barrier composed of an extracellular nuclease and restriction endonuclease in the unicellular cyanobacterium Microcystis sp.
Author(s) -
Takahashi Isamu,
Hayano Daisuke,
Asayama Munehiko,
Masahiro Futagami,
Watahiki Masanori,
Shirai Makoto
Publication year - 1996
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.1574-6968.1996.tb08564.x
Subject(s) - nuclease , microcystis aeruginosa , restriction enzyme , extracellular , biology , dna , endonuclease , isoschizomer , microbiology and biotechnology , biochemistry , cyanobacteria , chemistry , bacteria , genetics , gene , gene expression , dna methylation
The unicellular cyanobacterium Microcystis aeruginosa K‐81 has two types of restriction barrier, an extracellular nuclease and sequence‐specific endonuclease. The nuclease was detected in the culture supernatant and it was easily released from the cells by washing with water or buffer containing Triton X‐100. This nuclease was identified as a polypeptide of about 28 kDa that digested covalently closed circular and linear double‐stranded DNAs, including chromosomal DNA from M. aeruginosa K‐81. Among another 13 Microcystis strains examined, 3 produced an extracellular nuclease. Furthermore, M. aeruginosa K‐81 contained two sequence‐specific endonucleases, Mae K81I and Mae K81II, which were isoschizomers of Sp /I and Sau 96I, respectively.