Question

The tac promoter, an artificial promoter made from portions of the trp and lacUV5 promoters, has been introduced into a plasmid. It is a hybrid of the lac and trp (tryptophan) promoters, containing the −35 region of one and the −10 region of the other. This promoter directs transcription initiation more efficiently than either the trp or lac promoters. Why

Answer 1

answer and explanation

The tac promoter is more efficient than the trp and lac UV5 because as opposed to the trp and lac UV5 promoters, the tac promoter has both a consensus -35 sequence ( a nucleotide sequence of DNA, RNA or amino acids used for inter or intra molecular interactions) and a consensus pribnow box sequence ( a prokaryotic sequence with core element at -10 position).