Abstract
Our previous study showed that the amino acid sequence of Tetrahymena histone H 2 B has a blocked N-terminal residue followed by 119 amino acid residues, X-Pro-Lys…… [J. Biochem. (1982) 91, 897-904]. Now, X has been found to be N-trimethylalanine by 1H nuclear magnetic resonance spectroscopy of the isolated X-Pro-Lys and X. This identification was supported by mass spectrometry of X-Pro-Lys and by column and paper chromatography of X. This is the first time that N-terminal blocking by methylation has ever been found in histones.
