title: Characterization of a thermophilic ATP-dependent DNA ligase from the euryarchaeon Pyrococcus horikoshii.
abstract: Archaea encode a DNA ligase composed of a C-terminal catalytic domain typical of ATP-dependent ligases plus an N-terminal domain similar to that found in eukaryotic cellular and poxvirus DNA ligases. All archaeal DNA ligases characterized to date have ATP-dependent adenylyltransferase and nick-joining activities. However, recent reports of dual-specificity ATP/NAD+ ligases in two Thermococcus species and Pyrococcus abyssi and an ATP/ADP ligase in Aeropyrum pernix raise the prospect that certain archaeal enzymes might exemplify an undifferentiated ancestral stage in the evolution of ligase substrate specificity. Here we analyze the biochemical properties of Pyrococcus horikoshii DNA ligase. P. horikoshii ligase catalyzes auto-adenylylation and nick sealing in the presence of a divalent cation and ATP; it is unable to utilize NAD+ or ADP to promote ligation in lieu of ATP. P. horikoshii ligase is thermophilic in vitro, with optimal adenylyltransferase activity at 90 degrees C and nick-joining activity at 70 to 90 degrees C. P. horikoshii ligase resembles the ligases of Methanobacterium thermautotrophicum and Sulfolobus shibatae in its strict specificity for ATP.
authors.affiliation: Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10021, USA.
authors.forename: Niroshika
authors.initials: N
authors.lastname: Keppetipola
authors.forename: Stewart
authors.initials: S
authors.lastname: Shuman
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D019843:Archaeal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D001483:Base Sequence; D011088:DNA Ligases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D019641:DNA, Archaeal / Q000737:chemistry / Q000378:metabolism; D009690:Nucleic Acid Conformation; D009713:Nucleotidyltransferases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D043902:Pyrococcus horikoshii / Q000201:enzymology* / Q000235:genetics*; D013379:Substrate Specificity
chemical_list: D019843:Archaeal Proteins; D019641:DNA, Archaeal; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D009713:Nucleotidyltransferases; D011088:DNA Ligases