We all know about proteins, but do we know what it is made out of? Proteins have a structural formula made out of elements like histone. It gives structural support to the chromosomes so that the molecules can fit into the structure, and protein formation can happen. But did you know that a body comprises different histone protein types, and the classification is crucial for you to understand? If you do not have any insight about the same, it is time to gather some. Histone regulates the character of the gene and giving it a comprehensive shape. It is also a controlling factor of gene expression.
Classes Of Histone- Histone Protein Types
There are five histones categories- namely, H1/H5, H2A, H2B, H3, and H4. The histones in the name of H2A, H2B, H3, and H4 are rendered as core histones, but the other two are named as linker histones. All the core ones have some similarities in structure and are highly conservative when it comes to evolution. It undergoes easy dimerization and is available at the tail of the amino acid structure. These four categories of histones are responsible for the gene expression facility.
How Does Histone Interact With DNA?
Much research has been conducted about histone interaction, and the results are quite impressive. According to the researchers, histones are somewhat like spools that revolve around the DNA structure. It gives a compact shape to the DNA, and otherwise, it would have been a very long structure of about 1.8 meters. The histones help it come down to about 90 micrometers of chromatin, which is quite dense during the mitosis process. The assembly of DNA and histones is known as chromatin, and during the process of mitosis, there is a lot of interaction between regulatory proteins and nucleosomes.
Formation Of Nucleosome
One nucleosome forms when there are H2A-H2B dimers in one half and H3-H4 tetramer in the other. Therefore you can find the two symmetrical half in the tertiary structure. There are about 147 base pairs of DNA, which is wrapping around 1.6 Times and the shape is superhelical. The histone H1 attaches itself to the nucleosome and right at the entry and exit points. Therefore it locks the DNA into place and allows secondary order structure formation.
Five Types Of Interaction-Histone Protein Types
Because of the helix dipoles, there is an accumulation of charged phosphate groups in the DNA.
Hydrogen creates bonds between the DNA, and peptide creates a bond in the backbone of the proteins.
There is a collaboration of histone and deoxyribose sugar present in the DNA
Phosphate oxygen OS and amino acids undergo an interaction, and there is a communication between the Salt bridge and hydrogen bonds.
Lastly, there is specific groove insertion into the terminal tails of H3 and H2B in the DNA molecule to give it a compact and comprehensive shape.
Overall we can see that the hyperactive genes have fewer histones to lock them, while the inactive genes are associated with more histones. Several mutations can be malfunction if there is a lack of histones.