title: Single amino acid substitutions uncouple the DNA binding and strand scission activities of Fok I endonuclease.
abstract: Single alanine substitution mutations at Asp-450 or Asp-467 of the type IIS restriction enzyme Fok I have no effect on the ability of the enzyme to bind strongly and selectively to its recognition site but completely eliminate its ability to cleave either strand of substrate DNA. Since wild-type Fok I shows no kinetic preference or required order of strand cleavage, these results indicate that Fok I, which evidently functions as a monomer, uses a single catalytic center to cleave both strands of DNA. In this respect, Fok I may resemble other monomeric enzymes that cleave double-stranded DNA.
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
authors.forename: D S
authors.initials: DS
authors.lastname: Waugh
authors.forename: R T
authors.initials: RT
authors.lastname: Sauer
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D016384:Consensus Sequence; D004268:DNA-Binding Proteins / Q000737:chemistry*; D015252:Deoxyribonucleases, Type II Site-Specific / Q000737:chemistry*; D006868:Hydrolysis; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D004268:DNA-Binding Proteins; D009838:Oligodeoxyribonucleotides; C035042:endodeoxyribonuclease FokI; D015252:Deoxyribonucleases, Type II Site-Specific