Histone octamer
Encyclopedia
A histone octamer is an octamer of the histone
s found at the center of a nucleosome core particle. It consists of 2 copies of each of the four core histone proteins (H2A
, H2B
, H3
and H4
). The octamer assembles when a tetramer, containing two copies of both H3 and H4, complexes with two H2A/H2B dimers. These histones of the histone octamer all contain N-terminal tails that emanate from their central histone fold
s, and core domains with the C-terminals. The core domains are hydrophobic.
Histone
In biology, histones are highly alkaline proteins found in eukaryotic cell nuclei that package and order the DNA into structural units called nucleosomes. They are the chief protein components of chromatin, acting as spools around which DNA winds, and play a role in gene regulation...
s found at the center of a nucleosome core particle. It consists of 2 copies of each of the four core histone proteins (H2A
Histone H2A
Histone H2A is one of the 5 main histone proteins involved in the structure of chromatin in eukaryotic cells. Featuring a main globular domain and a long N terminal tail, H2A is involved with the structure of the nucleosomes of the 'beads on a string' structure.Other histone proteins...
, H2B
Histone H2B
Histone H2B is one of the 5 main histone proteins involved in the structure of chromatin in eukaryotic cells. Featuring a main globular domain and a long N terminal tail H2B is involved with the structure of the nucleosomes of the 'beads on a string' structure.See nucleosome, histone and...
, H3
Histone H3
Histone H3 is one of the five main histone proteins involved in the structure of chromatin in eukaryotic cells. Featuring a main globular domain and a long N-terminal tail, H3 is involved with the structure of the nucleosomes of the 'beads on a string' structure...
and H4
Histone H4
Histone H4 is one of the 5 main histone proteins involved in the structure of chromatin in eukaryotic cells. Featuring a main globular domain and a long N terminal tail, H4 is a structural component of the nucleosome, and is subject to covalent modification, including acetylation and methylation,...
). The octamer assembles when a tetramer, containing two copies of both H3 and H4, complexes with two H2A/H2B dimers. These histones of the histone octamer all contain N-terminal tails that emanate from their central histone fold
Histone fold
A histone fold is a fold found near the C-terminus of each type histone in a histone octamer. The core histones share a structurally conserved motif, the histone fold, averaging about 70 amino acids. The histone fold consists of three alpha helices connected by short loops....
s, and core domains with the C-terminals. The core domains are hydrophobic.