Question

In an experiment, you wanted to see which mutation will have worse effect on transcription. In the 1^st set you deleted 94 amino acids from the C-terminus and in the 2^nd set you replace the 265th C-terminal arginine to cystine. Which in your opinion will have the worst effect?

(a) 94 amino acid mutant

(b) 265^th amino acid mutant

(c) Both will have similar negative effect

(d) No visible effect on rate of transcription

I had been asked this question during an interview.

I'm obligated to ask this question of Transcription in Prokaryotes : Initiation topic in chapter Gene Expression : Transcription Prokaryotes of Cytogenetics

Answer 1

Right answer is (c) Both will have similar negative effect

To explain I would say: This is because the 265^th arginine is most important for recognition of the up element. Thus, its deletion alone can have a similar negative effect on transcription to the deletion of 94 amino acids from C terminal end.