title: I-ApeKI [corrected]: a novel intron-encoded LAGLIDADG homing endonuclease from the archaeon, Aeropyrum pernix K1.
abstract: Over 50 introns have been reported in archaeal rRNA genes (rDNAs), a subset of which nests putative homing endonuclease (HEase) genes. Here, we report the identification and characterization of a novel archaeal LAGLIDADG-type HEase, I-ApeKI [corrected], encoded by the ApeK1.S908 intron within the 16S rDNA of Aeropyrum pernix K1. I-ApeKI [corrected] consists of 222 amino acids and harbors two LAGLIDADG-like sequences. It recognizes the 20 bp non-palindromic sequence 5'-GCAAGGCTGAAAC downward arrowTTAAAGG and cleaves target DNA to produce protruding tetranucleotide 3' ends. Either Mn2+ or Co2+ can be substituted for Mg2+ as a cofactor in the cleavage reaction. Of the 20 bases within the minimal recognition site, 7 are essential for cleavage and are located at positions proximal to the cleavage sites.
authors.affiliation: Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University Kyoto 606-8502, Japan. nom@kais.kyoto-u.ac.jp
authors.forename: Norimichi
authors.initials: N
authors.lastname: Nomura
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Morinaga
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Shirai
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Sako
mesh_terms: D041522:Aeropyrum / Q000201:enzymology* / Q000235:genetics; D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D015252:Deoxyribonucleases, Type II Site-Specific / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D004706:Endodeoxyribonucleases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D007438:Introns; D017354:Point Mutation; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013379:Substrate Specificity
chemical_list: D019843:Archaeal Proteins; D012336:RNA, Ribosomal, 16S; D004706:Endodeoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific; C000608138:endodeoxyribonuclease ApeKI, Aeropyrum pernix