[Elongation of oligonucleotides covalently bound to the active center of RNA polymerase]

Elongation (mediated by RNA polymerase and NTPs) of the primer oligonucleotide residues, covalently fixed near the active centre of RNA polymerase, has been studied. Hepta- and octanucleotide residues covalently attached to beta-subunit could not be elongated (evidently, because the translocation step is prevented), whereas the same residues attached to sigma-subunit were easily elongated. It was concluded that ease of the oligonucleotide residue elongation is due to the dissociation of sigma-subunit from the transcription complex. The mechanism of this dissociation is discussed.