The creation of the Histone Database was stimulated by the X-ray analysis of the structure of the nucleosomal core histone octamer[2] followed by the application of a novel motif searching method to a group of proteins containing the histone fold motif in the early-mid-1990.

It has many interactive tools to explore and compare sequences of different histone variants from various organisms.

The core of the database is a manually curated set of histone sequences grouped into 30 different variant subsets with variant-specific annotations.

The curated set is supplemented by an automatically extracted set of histone sequences from the non-redundant protein database using algorithms trained on the curated set.

The interactive web site supports various searching strategies in both datasets: browsing of phylogenetic trees; on-demand generation of multiple sequence alignments with feature annotations; classification of histone-like sequences and browsing of the taxonomic diversity for every histone variant.