Related Experiment Video
Updated: Aug 17, 2026

High-throughput Purification of Affinity-tagged Recombinant Proteins
Published on: August 26, 2012
A protein kinase from wheat germ that phosphorylates the largest subunit of RNA polymerase II
1Department of Biochemistry, University of Missouri, Columbia, 65211.
Abstract:
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.
Related Concept Videos
Bacterial RNA Polymerase
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
Eukaryotic RNA Polymerases
All three eukaryotic RNAPs require specific transcription factors, of which the...
RNA Polymerase II Accessory Proteins
Transcription Initiation
The promoters and enhancers and their accessory proteins allow tight regulation of...
Eukaryotic RNA Polymerases
All three eukaryotic RNAPs require specific transcription factors, of which the...
RNA Polymerase II Accessory Proteins

