Chromatin / Flexibility

Chromatin / Flexibility

Chromatin (from Greek khrōma, which means  “color”)

Chromatin is the combination of DNA and proteins that make up the cell nucleus content. DNA molecule is a 2.5m long molecule that fits in the cell nucleus of only 5μm in diametre. To fit inside the tiny cell nucleus, DNA helix undergoes several levels of packaging.

At the primary level of DNA packaging the DNA double helix wraps around proteins (histones) forming nucleosomes; the “beads on a string” structure.

Multiple histones wrap into a 30 nm fibre consisting of nucleosome arrays in their most compact form. Further chromatin packaging leads to the formation of Scaffold and finally to the formation of chromosome. A human cell nucleus contains 46 chromosomes.

The packaging of DNA reflects the highly dynamic structure of the molecule and in the laB. world it is used as a metaphor for Flexibility.