title: A new class of site-specific endodeoxyribonucleases. Endo.Sce I isolated from a eukaryote, Saccharomyces cerevisiae.
abstract: We had found that yeasts had intracellular endodeoxyribonucleases that cut phage DNA into a set of double-stranded fragments with discrete chain lengths. We purified one of them to apparent homogeneity from Saccharomyces cerevisiae and designated it Endo.Sce I. Sequence analysis around 5 cleavage sites in plasmid DNA and phage DNA revealed that Endo.Sce I cuts a defined phosphodiester bond in each strand of double helix at the cleavage sites and produces free cohesive ends consisting of 4 nucleotides protruding at 3'-termini. However, unlike in the case of prokaryotic type II-restriction endonucleases, (i) Endo.Sce I seems to consist of two nonidentical subunits, (ii) no common palindrome or consensus sequence including more than 5 base pairs is detected at or near these cleavage sites, and (iii) Endo.Sce I can cut the DNA isolated from the cells that produced Endo.Sce I. All of the 5 cleavage sites are included in inverted repeats, but these inverted repeats are variable in size, nucleotide sequence, and distance between repeating units. An inverted repeat itself is not a structure recognized by Endo.Sce I. This study shows that Endo.Sce I is the first example of eukaryotic site-specific endonuclease and has properties, as described above, which distinguish it from prokaryotic restriction endonucleases.
mesh_terms: D001483:Base Sequence; D004262:DNA Restriction Enzymes / Q000302:isolation & purification* / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific; D008970:Molecular Weight; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins; D013379:Substrate Specificity
chemical_list: D004279:DNA, Viral; D029701:Saccharomyces cerevisiae Proteins; D004262:DNA Restriction Enzymes; C037725:SCEI protein, S cerevisiae; D015252:Deoxyribonucleases, Type II Site-Specific