Molecular Biology Which RNA polymerase II subunit resembles

Molecular Biology

Which RNA polymerase II subunit resembles the beta prime subunit of prokaryotic RNA polymerase? What is the evidence for this match?

Solution

Ans.) RNA polymerase have two alpa, one beta, one beta prime and one sigma subunit in the holoenzyme. Without sigma subunit RNA polymerase is called as the core RNA polymerase. RNA is synthesized in the same direction like DNA synthesis i.e. 5\' to 3\'. The RNA synthesis does not require a primer but it does need a DNA template strand. The first nucleotide of the RNA chain holds the 5\'-triphosphate group but the other subsequent nucleotides that are added to the nascent chain only keep the alpha phosphate in the phosphodiester linkage

In prokaryotes, the ’ subunit is the largest subunit and it is encoded by the rpoC gene. This \' subunit have active center, responsible for RNA synthesis and contains several determinants for non-sequence-specific interactions with DNA and newly formed RNA.

RNA polymerase II subunit RPB1 resembles to \' subunit   of prokaryotes as its main function is transcription (polymerization) of DNA to RNA. RNA polymerase II subunit RPB1 is encoded by the POLR2A gene and in yeast it is encoded by RPO21. It is the largest subunit of RNA polymerase II and contains a carboxy terminal domain (CTD) composed of up to 52 heptapeptide repeats (YSPTSPS) that are essential for polymerase activity.