title: An endo-exonuclease from meiotic tissues of the basidiomycete Coprinus cinereus. Its purification and characterization.
abstract: An endo-exonuclease has been identified and partially purified from the basidiocarp tissues of the basidiomycete Coprinus cinereus, which include synchronous meiosis at karyogamy-pachytene stages. Its peak activity appears during the meiotic prophase. The Coprinus endo-exonuclease has a single-strand specific endonuclease activity that converts the supercoiled DNA to relaxed DNA. The endonucleolytic cleavage of single-strand DNA generates 3'-phosphomonoester termini. It is also a single-strand-specific exonuclease and it hydrolyzes linear DNA in a 3' to 5' direction, but is unable to hydrolyze single-strand DNA having a 3'-phosphomonoester terminus. It requires Mg2+ with an optimal concentration of 25 mM. It has an optimal pH of 8.3, a peak enzyme activity at 50 degrees C, and it contains a single 43-kilodalton polypeptide. Coprinus meiotic endo-exonuclease may be involved in the substrate preparation for meiotic recombination.
authors.affiliation: Department of Molecular Biology and Genetics, University of Guelph, Ontario, Canada.
authors.forename: B C
authors.initials: BC
authors.lastname: Lu
authors.forename: K
authors.initials: K
authors.lastname: Sakaguchi
mesh_terms: D001487:Basidiomycota / Q000201:enzymology*; D003302:Coprinus / Q000201:enzymology*; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004720:Endonucleases / Q000302:isolation & purification* / Q000378:metabolism; D005092:Exonucleases / Q000302:isolation & purification* / Q000378:metabolism; D006868:Hydrolysis; D008540:Meiosis; D009691:Nucleic Acid Denaturation; D011995:Recombination, Genetic; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D004247:DNA; D004720:Endonucleases; D005092:Exonucleases; C020104:endoexonuclease