Structural analysis of the glycine-rich, arginine-rich histone. II. Sequence of the half of the molecule containing the aromatic amino acids.

1. The glycine-rich, arginine-rich histone from calf thymus was hydrolyzed with chymotrypsin; the peptides produced were fractionated on Sephadex G-25. The peptides containing the aromatic amino acids were purified by rechromatography on Sephadex G-25 and Aminex A-4 columns and by peptide mapping. 2. The six aromatic amino acids of the glycine-rich, arginine-rich histone were accounted for in eight peptides, including those found in the preceding study (Sautiere et al., J. Bio2. Chem., 243, 5899 (1968)). The sequence and order of these peptides were determined by analysis of the overlapping tryptic peptides. 3. All the aromatic amino acids were found to be in the carboxyl half of the glycine-rich, arginine-rich histone. The sequence of this portion, which includes 53 amino acids, is Ile-Tyr-Glu-Glu-Thr-Arg-Gly-Val-Leu-Lys-Val-PheLeu-Glu-Asx-Val-Ile-Arg-Asp-Ala-Val-Thr-Tyr-Thr -Glu His-Ala-Lys-Arg-Lys-Thr-Val-Thr-Ala-Met-Asp-Val-ValTyr-Ala-Leu-Lys-Arg-Gln-Gly-Arg-Thr-Leu-Tyr-Gly-PheGly-Gly-COOH.