a basic nuclear protein of the histone H3 family. May act as a core histone necessary for the assembly of centromeres. Contains a histone H3 related histone fold domain that is required for targeting to the centromere. CENPA is proposed to be a component of a modified nucleosome or nucleosome-like structure in which it replaces 1 or both copies of conventional histone H3 in the (H3-H4)2 tetrameric core of the nucleosome particle. Note: This description may include information from UniProtKB.