BIOL 483 Lecture Notes - Lecture 12: Alpha Helix, Nucleosome, Nucleoplasm
Document Summary
Short anchoring alpha helix structure allows nucleosome binding. > if tf binds to dna, it binds with alpha helix on either side of major groove without interfering with histones in order to bind nucleosomes. Extending anchoring alpha helix/ variable structure limits nucleosome binding. > if long alpha helices present, they interfere with histones, cannot bind nucleosomes. Viewed using nucleosomal array (13 nucleosomes with position stabilising sequences), middle nucleosome contains sequence that has binding site for tf of interest, look at nucleosomal array when chromatin compacts with linker histones. When tf binds -> local perturbations of nucleosomal structure. Fret of yeast tf in vivo looked at perturbations of nucleosome structure when tf binds. Chromatin compaction mediated by nucleosomes coming tgt in zig zag fashion. One face of nucleosome interacts with another face of a nucleosome (like a sandwich), so when. Tf comes in -> bust open one local nucleosome.
