What is the functional and structural distinction between core (H2A, H2B, H3,H4) and linker(H1/H5) histones?

Question

Many explanations of histone biochemistry isn't quite elucidating for the undergraduate student. How does histone structure (dimers, octomers) relate to their specific functions as core or linker histones? Also, how do both linker and core histones interact within nucleosomes to ultimately regulate gene expression?

Answer 1

Core histones interact with DNA through positive charges. Core histones can be acetylated, a part of the epigenetic regulation, in order to allow for gene expression. Acetyl groups contain negative charges, thus repelling the negative acidic charges of DNA. Linker Histones do not contain these properties.