The amino acid sequence of wheat histone H2B(12). A core histone with a novel repetitive N-terminal extension.

Two of the four electrophoretic histone H2B variants present in wheat embryos have been isolated. The complete primary structure of the H2B₍₂₎ variant has been deduced from sets of overlapping peptides generated by CNBr cleavage, Staphyloccocus aureus V8 protease, endoproteinase Arg-C, the post-proline cleaving enzyme, chymotrypsin and cleavage in dilute acid. A minimum of 17 peptides were required to establish the sequence. This variant has a blocked N terminus and comprises a total of 149 amino acids. The C-terminal two-thirds of the protein are highly homologous to vertebrate H2B. In contrast, the N-terminal third is entirely different and contains an N-terminal extension of 23 residues in which the sequence Ala-Glu-Lys or variants are repeated several times. This region is also highly homologous to the H2B from Tetrahymena pyriformis. It shows in addition similarities to wheat H2A₍₁₎ and bovine H1. [ABSTRACT FROM AUTHOR]