title: Restriction barrier composed of an extracellular nuclease and restriction endonuclease in the unicellular cyanobacterium Microcystis sp.
abstract: The unicellular cyanobacterium Microcystis aeruginosa K-81 has two types of restriction barrier, an extracellular nuclease and sequence-specific endonucleases. 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, MaeK81I and MaeK81II, which were isoschizomers of SplI and Sau96I, respectively.
authors.affiliation: Division of Biotechnology, School of Agriculture, Ibaraki University, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Takahashi
authors.forename: D
authors.initials: D
authors.lastname: Hayano
authors.forename: M
authors.initials: M
authors.lastname: Asayama
authors.forename: F
authors.initials: F
authors.lastname: Masahiro
authors.forename: M
authors.initials: M
authors.lastname: Watahiki
authors.forename: M
authors.initials: M
authors.lastname: Shirai
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004262:DNA Restriction Enzymes / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D046931:Microcystis / Q000201:enzymology* / Q000235:genetics; D015183:Restriction Mapping; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004247:DNA; D004262:DNA Restriction Enzymes