Extraordinary enhancement of the cleavage activity of a DNA-armed hammerhead ribozyme at elevated concentrations of Mg2+ ions.
As part of an ongoing effort to characterize structure-function relationships, activities of all-RNA and DNA-armed hammerhead ribozymes were examined. An analysis of the dependence on the concentration of Mg2+ ions of cleavage rates revealed that, whereas the kcat of the reaction catalyzed by the all-RNA ribozyme reached a maximum value of about 18 min-1 at a concentration of about 200 mM Mg2+ ions, that of the DNA-armed ribozyme increased linearly as the concentration of Mg2+ ions was increased above 300 mM, finally reaching a value of more than 100 min-1 at 700 mM Mg2+ ions. These results suggest that the potential activity of a hammerhead ribozyme might be greater than is usually recognized.
Shimayama
T
T
National Institute of Bioscience and Human Technology, Agency of Industrial Science and Technology, MITI, Tsukuba Science City, Japan.
Nishikawa
S
S
Taira
K
K
D001483:Base Sequence; D004247:DNA / Q000378:metabolism*; D003854:Deoxyribonucleotides / Q000378:metabolism; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009994:Osmolar Concentration; D016337:RNA, Catalytic / Q000138:chemical synthesis / Q000235:genetics / Q000378:metabolism*
D003854:Deoxyribonucleotides; D016337:RNA, Catalytic; D004247:DNA; D008274:Magnesium