Primary structure of histone H2A from gonads of the starfish Asterias rubens.

The complete amino acid sequence (124 residues) of histone H2A from gonads of the starfish Asterias rubens has been established from automated sequence analyses of large fragments obtained by staphylococcal protease digestion of histone H2A and by limited hydrolysis of H2A-H2B complex with mouse submaxillary gland protease and from structural studies of peptides generated by enzymatic hydrolyses of these fragments or of the protein. By comparison with calf homologous histone, the starfish histone H2A shows 5 deletions and 12 substitutions. Half of the substitutions are non-conservative. Microheterogeneities were found at positions 18, 40 and 50 and result in the existence of at least two variants of starfish gonad histone H2A.