Browsing by Subject "Histones"

Now showing 1 - 3 of 3
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    Histone/Serum Protein interactions, A cause of Pseudoimmunological reactions
    (1971) Worthington, Robert Walter
    Histones have been described by Murray (1964) as basic nuclear proteins which are at some time associated with DNA. Reviews on the biochemistry of histones have been written by Phillips (1962), Busch (1965 ), Butler, Johns and Phillips (1968), Hnilica (1967) and Bonner, Dabrnus, Fambrough, Huang, Marushige and Tuan (1968). These proteins are at present the subject of considerable interest because they are probably involved in the permanent repression of part of the genetic information of the DNA. If this is so, they must be basically involved in the control of cell differentiation.
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    Magnesium-dependent Association and Folding of Oligonucleosomes Reconstituted with Ubiquitinated H2A
    (2001) Jason, Laure J M; Moore, Susan C; Ausió, Juan; LINDSEY, George
    The MgCl2-induced folding of defined 12-mer nucleosomal arrays, in which ubiquitinated histone H2A (uH2A) replaced H2A, was analyzed by quantitative agarose gel electrophoresis and analytical centrifugation. Both types of analysis showed that uH2A arrays attained a degree of compaction similar to that of control arrays in 2 mM MgCl2. These results indicate that attachment of ubiquitin to H2A has little effect on the ability of nucleosomal arrays to form higher order folded structures in the ionic conditions tested. In contrast, uH2A arrays were found to oligomerize at lower MgCl2 concentrations than control nucleosomal arrays, suggesting that histone ubiquitination may play a role in nucleosomal fiber association.
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    The reconstitution of the histone octamer
    (1987) Greyling, H J; Von Holt, Claus; Sewell, Bryan Trevor
    This thesis describes methodology for the reconstitution of the chicken erythrocyte octamer from acid-denatured histones or the natural H3-H4 tetramer and H2A-H2B dimers. Oligomeric properties of reconstituted octamers were elucidated during column chromatographic and chemical cross-linking studies. The conformational identity of the natural and reconstituted octamers was demonstrated by the ability of all preparations to crystallise as helical octamer tubes. The application of the reconstitution methodology in addressing fundamental problems of chromatin research, was demonstrated during subsequent studies, namely (i) The reconstitution of hybrid histone octamers containing a structural variant of a specific histone. These studies were undertaken to study the effect on histone-histone interactions in hybrid octamers of which erythrocyte H2B was substituted for by sea urchin sperm H2B(l) or erythrocyte H3 and H4 were substituted for by dethiolated H3 and sea urchin sperm H4 respectively. (ii) The reconstitution of an octamer suitable for the sitespecific derivatisation of a specific histone, or covalently labelled with aurothiomalate in a specific histone complex. These studies were concluded to represent general labelling strategies which may be of use in crystallographic or physico-chemical studies of nucleosome structure.