MBB 331 Study Guide - Midterm Guide: Transcription Bubble, Phosphodiester Bond, Deoxyribonuclease

• School: Simon Fraser University
• Department: Molecular Biology and Biochemistry
• Course: MBB 331
• Professor: Jiarui Li

Document Summary

Core promoter: -10 and -35 consensus boxes. Increase promoter binding: change sequence in -10/-35/up to be more similar to consensus. -35: ttgaca: change distance between -35 and -10 to be 16bp, decrease distance between up and tss. Rnap holoenzyme: + ": catalytic center, 2 subunits: enzyme assembly and promotor recognition, w: not required, factor: responsible for promotor speci city, features. Three steps: rnap recognizes and binds to promotor: closed complex, rnap melt promotor dna: open complex, transcriptions experience either: Abortive initiation: 8-10 nts, most probable. Promoter clearance: displacement of subunit, rna exit channel opens, rnap moves away from tss. Stalls if incorrect nucleotide incorporated, allows reverse reaction: pyrophosphorolysis: nucleolytic. Polymeraze reverses direction to nucleotide before error and breaks rna phosphodiester bond. Topoisomerase relax strain: underwound negative right handed dna after transcription bubble, overwound positive left handed dna before transcription bubble.