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Cards In This Set
| Front | Back |
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M-phase chromatin is...?
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Tightly packed into visible chromosomes
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Most eukaryotic DNA is packaged into..
|
 Nucleosomes |
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DNA between nucleosomes is...
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 Linker DNA |
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DNA most tightly associated with the nucleosome is called..
|
 Core DNA (wrapper around histone core) |
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The histone core comprises these four histone proteins
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H2A . H2B . H3 . and H4
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Histone core is _____ charged
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Positively (this is why DNA -neg charged- associates with it
|
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all human
histones contain no less than 20% of these particular amino acids.
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Lysine and arginine (both pos charged)
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Histone fold domain
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which is
“conserved” (the same) for all the core
histones, can assemble intermediate structures
without DNA. (H2A/H2B diamer and H3/H4 tetramer
|
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Histone helices
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The cylinders represent protein “helices” (called
α-helices) that look a lot like a DNA helix!
|
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Histone H1
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Binds to linker DNA btw nucleosomes
|
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Histone h1 binds to 2 regions
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1) The linker DNA on one side of the nucleosome;
2) The center of the 147 bp “protected” DNA,
at the “dyad axis” (basically, the “center”).
|
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Size of fiber w/o H1
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W/o= 30nm
w=10nm
(closely together)
|
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Solenoid model
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 nucleosome discs are stacked on “edge” in the form of a helix, and the linker DNA is buried in thecenter of the “superhelix” but it never passes through or crosses the axis of the 30 nM fiber itself. |
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Zig-Zag model
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 the 30 nM fiber is a compacted form of “zigzag” nucleosome arrays, and the linker DNA must pass straight through the central axis of the fiber |
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"N" terminal tails
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Of core histones are CRUCIAL in forming 30nm fibers
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