Purification and characterization of mouse protamines, P1 and P2. Amino-acid sequence of P2

• Published in: Biochemistry (Easton) Vol. 27; no. 8; pp. 2890 - 2897
• Main Authors: Bellve, Anthony R, McKay, Donald J, Renaux, Bernard S, Dixon, Gordon H
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 19-04-1988
• Subjects: Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Cell Nucleus - analysis; Chromatography, High Pressure Liquid; Fundamental and applied biological sciences. Psychology; Holoproteins; Male; Mice; Molecular Sequence Data; Molecular Weight; Nuclear proteins; Peptide Fragments - isolation & purification; protamine P1; Protamines - isolation & purification; Proteins; Spermatozoa - analysis; Vertebrata; Mammalia; Mouse; Protamine; Semen; Rodentia; Primary structure
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi00408a034

Two mouse protamines, denoted as P1 and P2, have been purified directly from mature sperm nuclei and characterized as distinct polypeptide species. The complete primary structure of P2 was determined by peptide sequencing analyses. P1 and P2 were purified by a sequence of cation-exchange chromatography on Bio-Rex 70 and permeation chromatography on Bio-Gel P10, both in the presence of guanidine hydrochloride. Biochemical analyses demonstrate P1 has a molecular weight of 7400 and is characterized by the presence of arginine, cysteine, lysine, and tyrosine. By contrast, P2 is unusual in containing an abundance of arginine, histidine, lysine, and cysteine, but no tyrosine. The primary structure of P2 was determined from the sequencing of overlapping, high-pressure liquid chromatography purified peptides generated by thermolysin and endoproteinase Lys-C digestions and by chemical cleavage at each of four serine residues. Sequence analyses have demonstrated that P2, with a molecular weight of 8841, contains 62 amino acids, in the sequence NH2-Arg-Gly-His-His-His-His-Arg-His-Arg-Arg-Cys- Ser-Arg-Lys-Arg- Leu-His-Arg-Ile-His-Lys-Arg-Arg-Arg-Ser-Cys-Arg-Arg-Arg-Arg-Arg-His-Ser- Cys-Arg - His-Arg-Arg- Arg-His-Arg-Arg-Gly-Cys-Arg-Arg-Ser-Arg-Arg-Arg-Arg-Arg-Cys-Arg-Cys-Arg- Lys-Cys - Arg-Arg- His-His-COOH. Thus, the primary structure includes six clusters of arginine and histidine, distributed throughout the polypeptide, each ranging from five to eight amino acids in length. Sequence comparisons of mouse and human protamines by the Dayhoff program have revealed greater homology exists between human P2 and mouse P2 than within the P1 family from the two mammalian species.