DNA合成与修复.pptVIP

Protein Structure Function Content per cell Histone equivalents Gene HU Α and β subunit, 9KD each Compression of DNA, condensation of nucleus 40k polymers H2B hupA.B H 2 identical subunits, 28KD each 30k polymers H2A ？ IHF α：10.5KD β：9.5KD ATT point matching and recombination ？ ？ himA.D. H1 (H-NS) 15KD subunit Bonding DNA, topological structure DNA 10k polymers ？ osZ bglY pilG HLP1 17KD mono ？ 20k polymers ？ firA Stimulation DNA synthesis, in relation to lHF 2.2 Proteins binding to prokaryotic DNA 2. Organization of Prokaryotic Chromatin DNA loops Basic protein（binding proteins） Supercoiled DNA 2. Organization of Prokaryotic Chromatin 2.3.1 DNA loops 2. Organization of Prokaryotic Chromatin 2.3.2 Supercoiling Supercoiled dsDNA 2. Organization of Prokaryotic Chromatin 2.3.2 Supercoiling (a) Circular chromosomal DNA Formation of loop domains (b) Looped chromosomal DNA with associated proteins Loop domains DNA- binding proteins The looped structure compacts the chromosome about 10-fold Step1: compacted by loop domains 2. Organization of Prokaryotic Chromatin 2.4 Basic organizational process Step2: DNA supercoiling (b) Looped chromosomal DNA (c) Looped and supercoiled DNA Supercoiling Supercoiling within loops creates a more compact chromosome 2. Organization of Prokaryotic Chromatin RNA 350 μm 30 μm 2 μm Each loop is independently supercoiled. RNA cleaved Partial RNase digestion Partial DNase digestion Nicked DNA Nicked DNA Partially uncoiled chromosome Circular, unfolded chromosome Folded chromosome, actually 40 to 50 loops Supercoiled, folded chromosome 2. Organization of Prokaryotic Chromatin 2.4 Basic organizational process Partially unfolded chromosome PART THREE Organization of eukaryotic Chromatin Video： How DNA is Packaged 3. Organization of Eukaryotic Chromatin 3.1 Histones and formation of nucleosomes 3. Organization of eukaryotic Chromatin 3.1 Histones and formation of nucleosomes Nucleosomes showi