Question

The catalytic activity resides in which subunit of RNA polymerase?

(a) β′ (156 kDa)

(b) β (151 kDa)

(c) α (37 kDa)

(d) σ70 (70 kDa)

The question was asked by my college director while I was bunking the class.

This intriguing question originated from Transcription in Prokaryotes : Initiation in chapter Gene Expression : Transcription Prokaryotes of Cytogenetics

Answer 1

Correct answer is (a) β′ (156 kDa)

The best explanation: β′ and β subunits are mainly associated with the transcription start site where β′ subunit mainly confers the catalytic activity. The sigma subunit provides specificity while alpha subunit interacts with regulatory proteins.