histonebinding

Histone binding refers to the interactions between histone proteins that form nucleosomes and other molecules, including DNA, histone chaperones, reader proteins, enzymes, and small molecules. Histones H2A, H2B, H3, and H4 assemble into a core octamer around which DNA is wrapped, while linker histone H1 contributes to higher-order chromatin structure. Many proteins contain specialized domains that recognize and bind to histone surfaces or to post-translational modifications on histone tails, enabling coordinated regulation of chromatin.

Key histone-binding domains include bromodomains, chromodomains, plant homeodomain (PHD) fingers, Tudor domains, and others. Bromodomains preferentially bind acetylated lysines; chromodomains and PHD fingers often recognize methylated lysines such as H3K9me or H3K4me3. These interactions recruit transcriptional regulators, chromatin remodelers, and repair factors to specific genomic regions, influencing transcription, replication, and DNA repair. Histone chaperones and remodeling complexes also bind histones to facilitate nucleosome assembly, disassembly, and movement.

The functional significance of histone binding lies in modulating chromatin accessibility and epigenetic memory. Dynamic binding events can switch genes on or off, alter nucleosome spacing, and influence higher-order chromatin folding. Dysregulation of histone binding is implicated in developmental disorders and cancer. Researchers study histone binding using biochemical assays, structural biology, and genomic approaches, and pharmacological inhibitors targeting histone-binding domains (for example, BET inhibitors targeting bromodomains) are used in research and therapeutic contexts.