title: The amino acid sequence and interaction with the nucleosome core DNA of transition protein 4 from boar late spermatid nuclei.
abstract: The primary structure of transition protein 4 (TP4) from boar late spermatid nuclei was determined by automated Edman degradation of S-pyridylethylated protein and of peptides generated by cleavage with Staphylococcus aureus V8 protease, lysyl endopeptidase and CNBr. Boar TP4 is a basic protein consisting of a highly basic amino-terminal half (residues 1-73) and a less basic carboxy-terminal half (residues 74-138). The latter half includes a highly hydrophobic segment, a four-times tandemly repeated sequence, N(G)QNKR(K)X, and a carboxy-terminal segment containing Trp126. Ultraviolet absorption and CD spectra of TP4-rat-liver-nucleosome-core-DNA (double-stranded DNA) complexes suggest a TP4-induced local melting of DNA. Although at 1 mM NaCl TP4 brought about a slight stabilization of the DNA against thermal melting, a destabilization of the DNA was observed at 50 mM NaCl. From the results of quenching of tryptophan (Trp126) fluorescence of TP4 upon its binding to double-stranded and single-stranded boar liver nucleosome-core DNA at 50 mM NaCl, the apparent association constants for the binding of TP4 to double-stranded and single-stranded DNA were calculated to be 7.3 x 10(3) M-1 and 4.1 x 10(3) M-1, respectively. These results suggest that TP4, having different domain structures from TP1-3 and a higher affinity for double-stranded DNA, induces a local destabilization of DNA probably through the stacking of Trp126 with nucleic acid bases.
authors.affiliation: Department of Chemistry, Faculty of Science, Chiba University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Akama
authors.forename: H
authors.initials: H
authors.lastname: Ichimura
authors.forename: H
authors.initials: H
authors.lastname: Sato
authors.forename: S
authors.initials: S
authors.lastname: Kojima
authors.forename: K
authors.initials: K
authors.lastname: Miura
authors.forename: H
authors.initials: H
authors.lastname: Hayashi
authors.forename: Y
authors.initials: Y
authors.lastname: Komatsu
authors.forename: M
authors.initials: M
authors.lastname: Nakano
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009691:Nucleic Acid Denaturation; D009707:Nucleosomes / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D012091:Repetitive Sequences, Nucleic Acid; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013087:Spermatids / Q000378:metabolism*; D013552:Swine
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D009707:Nucleosomes; C053886:spermatid transition proteins; D004247:DNA