HeLa cells contain a 2'-phosphate-specific phosphotransferase similar to a yeast enzyme implicated in tRNA splicing.
We have previously shown that HeLa cells contain activities implicated in tRNA splicing in yeast, a ligase capable of joining tRNA half-molecules and an NAD-dependent activity capable of removing the 2'-phosphate created at the splice junction by the ligase (Zillmann, M., Gorovsky, M.A., and Phizicky, E.M. (1991) Mol. Cell. Biol. 11, 5410-5416). We show here that removal of the splice junction 2'-phosphate is, as in yeast, a 2'-phosphate-specific phosphotransfer reaction that produces the same, as yet unidentified, small molecule. This enzyme is highly specific for oligomeric substrates having internal 2'-phosphates. Oligomers bearing terminal 2'-phosphates are at least 50-fold less reactive and those bearing 5'- or 3'-terminal phosphates are at least 600-fold less reactive. The requirement for an internal 2'-phosphate can be satisfied by a substrate as small as a dimer.
Zillmann
M
M
Department of Biology, University of Rochester, New York 14627.
Gorovsky
M A
MA
Phizicky
E M
EM
D001345:Autoradiography; D001483:Base Sequence; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D010770:Phosphotransferases / Q000378:metabolism*; D012326:RNA Splicing; D012343:RNA, Transfer / Q000378:metabolism*; D015003:Yeasts / Q000201:enzymology
D012343:RNA, Transfer; D010770:Phosphotransferases