A protein kinase from wheat germ that phosphorylates the largest subunit of RNA polymerase II.
A protein kinase from wheat germ that phosphorylates the largest subunit of RNA polymerase IIA has been partially purified and characterized. The kinase has a native molecular weight of about 200 kilodaltons. This kinase utilizes Mg2+ and ATP and transfers about 20 phosphates to the heptapeptide repeats Pro-Thr-Ser-Pro-Ser-Tyr-Ser in the carboxyl-terminal domain of the 220-kilodalton subunit of soybean RNA polymerase II. This phosphorylation results in a mobility shift of the 220-kilodalton subunits of a variety of eukaryotic RNA polymerases to polypeptides ranging in size from greater than 220 kilodaltons to 240 kilodaltons on sodium dodecyl sulfate-polyacrylamide gels. The phosphorylation is highly specific to the heptapeptide repeats since a degraded subunit polypeptide of 180 kilodaltons that lacks the heptapeptide repeats is poorly phosphorylated. Synthetic heptapeptide repeat multimers inhibit the phosphorylation of the 220-kilodalton subunit.
Guilfoyle
T J
TJ
Department of Biochemistry, University of Missouri, Columbia, 65211.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D015180:Electrophoresis, Gel, Two-Dimensional; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010940:Plant Proteins / Q000378:metabolism*; D011494:Protein Kinases / Q000302:isolation & purification / Q000378:metabolism*; D012319:RNA Polymerase II / Q000737:chemistry / Q000378:metabolism*; D014908:Triticum / Q000201:enzymology*
D010940:Plant Proteins; D000255:Adenosine Triphosphate; D011494:Protein Kinases; D012319:RNA Polymerase II; D008274:Magnesium