BIO 121 Lecture Notes - Lecture 4: Micrococcal Nuclease, Histone H2B, Intron
23 Nov 2020
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Document Summary
Proteins contain a nuclear export signal (different from import signal) that binds with a receptor complex binds to the pore after transport the receptor and protein dissociate. Non histone chromatine associated proteins- heterogenous group interacting with dna or histones. Regulate organization of chromosomes and regulate gene extression. Histones set of basic proteins (positive charge) that interact with dna. H2a, h2b, h3, h4 are core histones interact strongly with each other and dna to form a nucleosome. Dna between nucleosomes is called linker dna. H1 binds to the outside of the nucleosome and packs all the nucleosomes together to tightly back dna. 11nm fibre nucleosomes are separated by linker dna: not typically found in a live cell. Condensed into the 30nm fibre through interaction with h1: h1 is ~2x the weight of other histones, less hydrophobic. 30nm fibre undergoes further packing in interphase through help of non-histone scaffolding proteins. Make chromosomal loops with genes exposed at the ends of the loops.
