Histones Organize DNA Into Compact & Manageable Structures
- If you tried packing a long rope into a small box without a proper system, it would tangle and overflow.
- DNA faces a similar challenge, as it fits nearly 2 meters of material into a microscopic nucleus.
- The solution is histones.
Definition
Histone
A protein that provides structural support for DNA in eukaryotic cells. Histones are positively charged, allowing them to interact with negatively charged DNA, helping to compact it into a condensed form called chromatin.
How Is DNA Wrapped Around Histones?
- DNA wraps around a core of eight histone proteins like a thread around a spool.
- These eight histones form an octamer that serves as the foundation for DNA wrapping.
- This is also referred to as a nucleosome.
Definition
Nucleosome
A nucleosome is the basic structural unit of chromatin, consisting of DNA wrapped around a core of histone proteins.
Components of a Nucleosome
- Histone Core
- Composed of eight histone proteins: two copies each of H2A, H2B, H3, and H4.
- This core forms the foundation for DNA wrapping.
