Lys & Arg have four ionisations zones

1. 1--------pK1 – charge +2

2. pK1---------pK2 charge +1

3. pK2---------pKr charge 0

4. pKr---------14 charge -1

TLS Online TPP Program

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#Unit 2. Cellular Organization

H32-H42 tetramer accounts for the diameter of the octamer. It forms the shape of a horseshoe.

TLS Online TPP Program

#Id: 450

#Unit 2. Cellular Organization

All four core histones show a similar type of structure in which three a-helices are connected by two loops. This highly conserved structure is called the histone fold.

TLS Online TPP Program

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#Unit 2. Cellular Organization

Nucleosomes that contain linker H1 histones are referred to as chromatosomes.

TLS Online TPP Program

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#Unit 2. Cellular Organization

Lysine  in the histone tails are the most common targets of modification.

TLS Online TPP Program

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#Unit 2. Cellular Organization

Acetylation, methylation, ubiquitylation, and sumoylation all occur on the free epsilon amino group of lysine.

TLS Online TPP Program

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#Unit 2. Cellular Organization

Acetylation neutralizes the positive charge of lysine so disrupts DNA Histone interactions.