A RecB-family nuclease motif in the Type I restriction endonuclease EcoR124I.
The Type I restriction-modification enzyme EcoR124I is an ATP-dependent endonuclease that uses dsDNA translocation to locate and cleave distant non-specific DNA sites. Bioinformatic analysis of the HsdR subunits of EcoR124I and related Type I enzymes showed that in addition to the principal PD-(E/D)xK Motifs, I, II and III, a QxxxY motif is also present that is characteristic of RecB-family nucleases. The QxxxY motif resides immediately C-terminal to Motif III within a region of predicted alpha-helix. Using mutagenesis, we examined the role of the Q and Y residues in DNA binding, translocation and cleavage. Roles for the QxxxY motif in coordinating the catalytic residues or in stabilizing the nuclease domain on the DNA are discussed.
Institute of Microbiology v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Eva
E
Sisáková
Louise K
LK
Stanley
Marie
M
Weiserová
Mark D
MD
Szczelkun
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D004247:DNA / Q000378:metabolism; D015253:Deoxyribonucleases, Type I Site-Specific / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D043211:Exodeoxyribonuclease V / Q000737:chemistry; D007700:Kinetics; D008969:Molecular Sequence Data; D016296:Mutagenesis; D021122:Protein Subunits / Q000737:chemistry; D021381:Protein Transport; D016415:Sequence Alignment
D021122:Protein Subunits; D004247:DNA; D043211:Exodeoxyribonuclease V; C048242:endodeoxyribonuclease EcoR124I; D015253:Deoxyribonucleases, Type I Site-Specific