Affinity labeling of RNA-polymerase II in the transcriptionally active complex by a phosphorylating analog of the initiation substrate

Biochemistry (Mosc). 2000 Oct;65(10):1129-34.


Affinity modification of RNA-polymerase II by a phosphorylating analog of the initiation substrate carrying a zwitterionic 5;-terminal phosphate group with a 4-N,N-dimethylaminopyridine residue (DMAP-pA) was studied during specific transcription initiation controlled by the late adenoviral promotor. Super-selective affinity labeling and standard conditions of affinity modification resulted in labeling a polypeptide with molecular weight corresponding to that of the third subunit of the enzyme, RPB3 (45 kD). The initiation substrate (ATP) protects RNA-polymerase II from modification. The third subunit may be involved in the formation of the substrate-binding site of the enzyme.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4-Aminopyridine / analogs & derivatives*
  • Affinity Labels
  • Base Sequence
  • Phosphorylation
  • RNA Polymerase II / metabolism*
  • RNA, Fungal / genetics
  • RNA, Fungal / metabolism
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics
  • Substrate Specificity
  • Transcription Factors / metabolism
  • Transcription, Genetic


  • Affinity Labels
  • RNA, Fungal
  • Transcription Factors
  • 4-Aminopyridine
  • RNA Polymerase II
  • 4-dimethylaminopyridine