Main description:

The histones are now a very well established part of Biochemistry. The interpretation of all that is known about them, however, is already too great a burden for a single author to undertake. Indeed, a survey of the indexed literature shows that the number of publications on the histones has approximately doubled in every three years for the past 15 years, and is now several hundred a year. It is time then to bring together in one publication the major topics embraced by this great research effort. This book therefore endeavours to give, in six chapters, a broad and searching account of the biochemistry and biophysics of these interesting proteins and their complexes with nucleic acids, the nucleohistones. Each chapter is written by different authors who are all active in this research and who have had many years experience with these proteins and their complexes. Chapters 1, 2, part of 3, and all of Chapters 5 and 6, cover the occurrence, preparation, characterization, sequence structure, bio physical properties and finally, the biosynthesis and functions of the histones. The other part of Chapter 3, the whole of Chapter 4 and to a less extent some other chapters, all discuss the properties and structure of the nucleohistones. The study of these complexes is undoubtedly of great importance in bridging the gaps in our knowledge of template activity and differentiation as well as of chromosomal structure and mechanics.

Contents:

1 The Preparation and Characterization of Histones.- 1.1 Introduction.- 1.1.1 Historical.- 1.2 Definition of Histones.- 1.3 Occurrence of Histones.- 1.3.1 Multicellular organisms.- 1.3.2 Unicellular organisms.- 1.4 Preparation of Whole Histone.- 1.4.1 Isolation of deoxyribonucleoprotein (DNP).- 1.4.2 Preparation of whole histone from DNP.- (a) Acid extraction.- (b) Salt dissociation.- 1.5 Preparation of Whole Protamine.- 1.6 Fractionation Procedures for Whole Histone.- 1.6.1 Column chromatography.- 1.6.2 Other methods.- 1.7 Selective Extraction Procedures.- 1.7.1 Selective dissociation with salts.- 1.7.2 Selective extraction with acid.- 1.7.3 Selective extraction using organic solvents.- 1.8 Fractionation Procedures Applied to Histones for Their Further Subdivision or Purification.- 1.8.1 Methods for the separation of specific mixtures of fractions.- 1.8.2 Further purification and subdivision of the five main histone fractions.- 1.9 Complexity and Heterogeneity of Histones.- 1.10 The Fractionation of Protamine.- 1.11 Histone Specificity.- 1.12 Characterization of Histones.- 1.12.1 Amino acid composition.- 1.12.2 Gel electrophoresis.- 1.12.3 Other methods.- 1.12.4 Quantitative determination.- 1.13 Unusual Histones or Nuclear Proteins.- 1.14 A Comparison of Histone Fractions and Nomenclatures.- 1.15 The Aggregation of Histones.- 1.16 Other General Properties of Histones.- 2 The Primary Structure of Histones and Protamines.- 2.1 Introduction.- 2.2 Methods Used in Amino Acid Sequence Work with Histones.- 2.2.1 Increasing the specificity of trypsin.- 2.2.2 The use of other proteolytic enzymes.- 2.2.3 Chemical methods used for degrading histones for sequence determination.- 2.3 The Primary Structure of Histone F1(I).- 2.4 The Primary Structure of Histone F2B(IIb2).- 2.5 The Primary Structure of Histone F2A2(IIbl).- 2.6 The Primary Structure of Histone F2A1(IV).- 2.7 The Primary Structure of Histone F3(III).- 2.8 The Primary Structure of Protamines.- 2.9 Histone Sequence and Histone Evolution.- 2.9.1 Internal homology in protamine and histone sequences.- 2.9.2 Comparison of the sequences of different histones.- 2.10 The Primary Structure of Histones in Relation to the Structure of Deoxyribonucleohistone.- 3 Physical and Conformational Studies of Histones and Nucleohistones.- 3.1 Introduction.- 3.2 Histones.- 3.2.1 Molecular weights of histones and aggregation.- 3.2.2 Analysis of the primary structure of histones for possible conformations.- 3.2.3 Physical studies of the conformations of histones.- Histones in the solid state.- Optical Rotatory Dispersion studies of histones in solution.- Nuclear Magnetic Resonance Spectroscopic studies of histones.- 3.3 The Conformation of Nucleohistone.- 3.3.1 X-Ray diffraction studies of nucleohistones.- 3.3.2 Evidence for the "supercoiled" form of nucleohistone.- 3.3.3 Factors involved in the "supercoiled" structure.- 3.3.4 Conformation of DNA and histones in nucleohistone.- Spatial arrangements of histones on DNA.- 3.4 Partial Nucleoproteins.- 3.4.1 Dissociation of histones from nucleohistones.- 3.4.2 Physical studies of partial nucleohistones.- 3.4.3 Loss of superstructure on histone removal.- 3.5 Recombination of Histones with DNA.- 3.6 A Structural Role for Histones.- 4 The Chemical and Physical Properties of Nucleohistones.- 4.1 The Preparation and Composition of Nucleo-Histones.- 4.1.1 Preparative procedures.- 4.1.2 The composition of nucleohistones.- Nucleic acids.- Proteins.- Acidic proteins.- Histones.- 4.2 Physico-Chemical Properties of Nucleohistones.- 4.2.1 Solubility.- 4.2.2 Gel-forming properties.- 4.2.3 Size and shape.- 4.2.4 Charge and titration.- 4.2.5 Structural studies on nucleohistones and nucleoprotamines.- Conformation of nucleohistones.- Anisotropy and orientation of chromophores.- Conformation of nucleoprotamines.- Ultraviolet spectra of nucleohistones.- 4.3 Interactions of DNA and Nucleohistones with Other Molecules.- 4.3.1 Interactions of DNA with small molecules and polybases.- DNA-protamine interactions.- 4.3.2 Interactions of DNA with histones.- 4.3.3 Dissociation and reassociation of nucleohistones in salt solution.- Characteristics of the dissociation process.- Properties of reassociated nucleohistones.- 4.3.4 Properties of protein-depleted nucleohistones.- 4.3.5 Interactions of nucleohistones with small cations and molecules.- 4.3.6 Interactions of nucleohistones with metal cations.- 4.4 General Conclusions and Structural Aspects.- 4.4.1 Nature of the bonds between histones and DNA.- 4.4.2 Structural hypotheses.- 5 Histone Biosynthesis and the Cell Cycle.- 5.1 Introduction.- 5.2 Histone Synthesis.- 5.2.1 Cellular localization of histone synthesis.- 5.2.2 Rates of biosynthesis of individual histone fractions.- 5.2.3 Histone turnover.- 5.2.4 Extracellular factors affecting histone synthesis.- 5.2.5 Histone synthesis during the cell cycle.- 5.3 Histone Synthesis in Gametes and During Embryogenesis.- 5.3.1 Histones in meiosis.- 5.3.2 Arginine-rich proteins of male gametes.- 5.3.3 Histone synthesis in embryos.- 5.4 The Integrity of Chromatin.- 6 Functional and Metabolic Aspects of DNA-Associated Proteins.- 6.1 Introduction.- 6.1.1 On the relationship between chromosomal structure and function.- 6.1.2 The chromosomal localization of histones and protamines.- 6.1.3 The problem of histone specificity.- 6.2 The Effect of Histones in the Cell.- 6.2.1 Histone effects on RNA synthesis.- 6.2.2 Histone effects on DNA synthesis.- 6.2.3 Histone effects on cell function-some general observations.- 6.3 Enzymatic Modifications of Histone Structure.- 6.3.1 Histone methylation-methylated lysines.- ?-N-methyl-arginine in histones.- Evidence for 3-methyl histidine in histones.- Methylation of histone carboxyl groups.- 6.3.2 Histone acetylation.- ?-N-acetyllysine in histones-occurrence and formation.- Physiological aspects of histone acetylation.- Correlations between NH2-terminal acetylation and histone synthesis.- 6.3.3 Thiol/disulfide conversions in the F3(III) histone fraction.- 6.3.4 Histone phosphorylation.- 6.3.5 Histone structural modifications-some general conclusions.- 6.4 Changes in Acidic Chromosomal Proteins at Times of Gene Activation.