Crab claw"shape of RNAP (The shape of dNA pol is) Active center cleft 16
16 “Crab claw” shape of RNAP (The shape of DNA pol is__) Active center cleft
There are various channels allowing DNA, RNA and ribonucleotides(rNTPs) into and out of the enzymes active center cleft 17
17 There are various channels allowing DNA, RNA and ribonucleotides (rNTPs) into and out of the enzyme’s active center cleft
Transcription by RNA a polymerase proceeds n in a series of steps ■ Initiation 中a9 Elongation ■ Termination 18
18 Transcription by RNA polymerase proceeds in a series of steps ◼ Initiation ◼ Elongation ◼ Termination RNA polymerase and the transcription cycle
Initiation Promoter: the DNA sequence that initially binds the RNa polymerase a The structure of promoter- polymerase complex undergoes structural changes to proceed transcription a DNA at the transcription site unwinds and a“ bubble” forms a Direction of RNA synthesis occurs in a 5-3, direction(3-end growing) 19
19 Initiation ◼ Promoter: the DNA sequence that initially binds the RNA polymerase ◼ The structure of promoterpolymerase complex undergoes structural changes to proceed transcription ◼ DNA at the transcription site unwinds and a “bubble” forms ◼ Direction of RNA synthesis occurs in a 5’-3’ direction (3’-end growing)
s Transcription initiation a involves 3 defined steps 1. Forming closed complex 2. Forming open complex 3. Promoter escape: stable a ternary complex 0 20
20 Transcription initiation involves 3 defined steps 1. Forming closed complex 2. Forming open complex 3. Promoter escape: stable ternary complex RNA polymerase and the transcription cycle