mRNA-decapping enzyme from Saccharomyces cerevisiae: purification and unique specificity for long RNA chains.
An enzyme that hydrolyzes one PPi bond of the cap structure of mRNA, yielding m7GDP and 5'-p RNA was purified from Saccharomyces cerevisiae to a stage suitable for characterization. The specificity of the enzyme was studied, using both yeast mRNA and synthetic RNAs labeled in the cap structure. A synthetic capped RNA (540 nucleotides) was not reduced in size, while as much as 80% was decapped. Yeast mRNA treated with high concentrations of RNase A, nuclease P1, or micrococcal nuclease was inactive as a substrate. The use of synthetic capped RNAs of different sizes (50 to 540 nucleotides) as substrates showed that the larger RNA can be a better substrate by as much as 10-fold. GpppG-RNA was hydrolyzed at a rate similar to that at which 5'-triphosphate end group were not hydrolyzed.
Stevens
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Biology Division, Oak Ridge National Laboratory, Tennessee 37831.
D005656:Fungal Proteins / Q000302:isolation & purification* / Q000378:metabolism; D008970:Molecular Weight; D011755:Pyrophosphatases / Q000302:isolation & purification* / Q000378:metabolism; D012315:RNA Caps / Q000378:metabolism*; D012331:RNA, Fungal / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013379:Substrate Specificity
D005656:Fungal Proteins; D012315:RNA Caps; D012331:RNA, Fungal; D011755:Pyrophosphatases; C021899:nucleotide pyrophosphatase