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Query: HUMANGGP:040116 (histone)
 44,835 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Highly specific antibodies were raised to histone 1 (H 1) and the histone complexes H32-H42 AND H2A-H2B, isolated by salt extraction. Antibody to H1 could detect irreversible conformational changes in acid- or urea-treated H1. The antibodies showed different reactivities with chromosomes as compared to antibodies in acid-extracted histones and should be useful in studies of native chromatin and chromosome structure.
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PMID:Antibodies to histones and histone-histone complexes: immunochemical evidence for secondary structure in histone 1. 0 53

It has been shown by high-resolution proton magnetic resonance (PMR) spectroscopy and circular dichroism (CD) that an H2A/H2B histone complex exists after salt extraction of these histones from chromatin and that this complex can be fully renatured from both urea-denatured acid-extracted and from urea-denatured salt-extracted histones. The histone complex is shown to involve specific secondary and tertiary structure. Formation of this complex is observed to be critically dependent on pH, occurring at and above pH 5. It cannot be induced below pH 5 by increase in ionic strength. From CD spectra the H2A/H2B complex is shown to contain about 37% alpha helix but no beta structure, the latter being confirmed by infrared spectroscopy in the 6-mum region. The PMR spectra show that the structured region includes most of the aromatic residues of both histones, at least two histidine residues of H2B and probably histidines 31 and 82 of histone H2A. The secondary structure of histones H2A and H2B is predicted using the Chou and Fasman procedure and comparisons are made between the predictions for histones of different species. These results in conjunction with the experimental evidence lead to the conclusion that at least residues 31-95 of H2A and residues 37-114 of H2B, i.e. the more apolar regions of the molecules, are involved in the tertiary structure of the H2A/H2B complex.
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PMID:A pH-dependent interaction between histones H2A and H2B involving secondary and tertiary folding. 1 62

Calf liver contains two nuclear N-acetyltransferases which are separated by chromatography on hydroxylapatite. Both acetyltransferase A and acetyltransferase B will transfer acetate from acetyl-CoA to either histone or spermidine. The same protein catalyzes the reaction with both substrates; this is shown by a constant ratio of spermidine to histone activity over a 5,000-fold purification and identical heat denaturation kinetics for both spermidine and histone acetyltransferase activity with each enzyme. Histone is preferentially acetylated when both acceptors are present. Both enzymes preferentially acetylate polyamines (spermidine, spermine, and diaminodipropylamine) to diamines. Acetyltransferase A acetylates histones in the order: whole histone greater than H4 greater than H2A greater than H3 greater than H2B greater than H1; acetyltransferase B in the order: whole histone greater than H4 = H3 greater than H2A greater than H2B greater than H1. Michaelis constants are 2 X 10(-4)M for spermidine and 9 X 10(-6)M for acetyl-CoA. Acetyltransferase A has a molecular weight of 150,000; acetyltransferase B 175,000. Both enzymes are strongly inhibited by p-chloromercuribenzoate and weakly inhibited by EDTA.
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PMID:Calf liver nuclear N-acetyltransferases. Purification and properties of two enzymes with both spermidine acetyltransferase and histone acetyltransferase activities. 2 43

The interactions of H1 (H1A, H1B), H2A, H2B, H3, H4, and H5 with phenyl cross-linked agarose were studied. Procedures are described whereby all six histones can be bound, released, and fractionated by using appropriate salt concentrations or pH. The binding can be totally abolished by inclusion of hydrophobic disrupting agents. Control experiments with nonderivated cross-linked agarose ruled out a passive aggregation-disaggregation phenomenon governing the binding patterns. The absorption sequence based on the identification and quantitation of individual histones from either unfractionated (whole) histone or separate histone classes is as follows: H3 greater than or equal to H4 greater than H2B greater than or equal to H5 greater than or equal to H2A greater than H1A greater than or equal to H1B. The order differs only slightly from the reverse of the desorption sequence, H1B less than or equal to H1A less than or equal to H5 less than H2A less than or equal to H3. Preferential interaction of H2A-H2B, H3-H4, and H2A-H2B-H4 occur; these interactions can modify the original relative affinity of each individual component for the matrix. The variability in matrix affinity appears to involve simple stoichiometry of the histone components.
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PMID:Fractionation of avian erythrocyte histones by hydrophobic interaction chromatography. 3 71

A complement fixation study with human, monkey and rabbit sera, using purified sperm nuclear basic proteins as antigens, led to the following conclusions. (1) Protamines, the sperm-specific basic nuclear proteins, may be immunogenic in mammalians. (2) Antibodies detected in the indirect immunofluorescence test on human swollen sperm heads in sera from infertile and vasectomized men, are directed primarily against human protamines. (3) The results obtained suggested that differences in the immunization site and/or in the configuration of the immunizing protamine, may lead to the formation of antibodies directed against different antigenic determinants. Autoimmunity to protamines, following vasectomy or in infertile men, is accompanied by the formation of antibodies cross-reacting with common antigenic determinants present in protamines of other species. Induction of immunity to protamines by means of immunization with protamines-RNA complexes (in rabbits), or protamine-insulin complexes (in humans), leads to the formation of antibodies reacting more specifically with the immunizing protamine, showing only slight cross-reaction with other protamines. (4) The histone-like fraction present in mature human spermatozoa is composed mainly of histone fraction H2B.
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PMID:Studies on the immunogenicity of protamines in humans and experimental animals by means of a micro-complement fixation test. 10 75

The complete sequence of histone 2B of Drosophila has been determined by using an improved Beckman sequenator. Comparing these data with those previously published by other investigators on the histone 2B of calf [Iwai, K., Hayashi, H., & Ishikawa, K. (1972) J. Biochem. (Tokyo) 72, 357--367], trout [Koostra, A., & Bailey, G. S. (1978) Biochemistry 17, 2504--2510], and Patella (a limpet) [van Helden, P. D., Strickland, W. N., Brandt, W. F., & von Holt, C. (1979) Eur. J. Biochem. 93, 71--78], it is possible to assess the evolutionary stability of this protein. There is little conservation of sequence in the N-terminal portion of the molecule (residues 1--26 numbering according to calf H2B), while the remainder of the protein, which we designate the C-terminal portion, is highly conserved. In the region of 27--125 residues, there are 9 substitutions in the composite data among the 98 positions, 8 of them conservative. These data indicate that very different selective pressures operate on the two different portions of the H2B molecule, implying the existence of two well-defined regions. Studies on the structure of the nucleosome by others have suggested that the C-terminal portion of H2B is involved in histone-histone interactions while the N-terminal portion is a relatively free "tail" binding to DNA. The sequence data indicate that the function of the C-terminal region of H2B requires considerable sequence specificity while that of the N-terminal region does not.
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PMID:Sequence of histone 2B of Drosophila melanogaster. 11 30

Chicken erythrocyte chromatin and nuclei were labeled with benzo[alpha]-pyrene (B[alpha]P) diol-epoxide (anti) and digested with micrococcal nuclease to mono- and dinucleosomes. Analysis of the distribution of the carcinogen showed that the internucleosomal region bound 3-4 times more carcinogen per unit DNA than did nucleosomes. The enhanced binding of the 'ultimate' carcinogen to the internucleosomal region was similar when isolated chromatin or nuclei were used for in vitro labeling. Furthermore, isolation of the histone core proteins, H2A, H2B, H3 and H4, revealed that only 15% of the carcinogen was associated with the histones and that the majority of the carcinogen was bound to chromosomal DNA. Fluorography of purified nucleosomal histones showed that the covalent association of the carcinogen was mainly with histones H3 and H2B.
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PMID:Interaction of benzo[alpha]pyrene diol-epoxide with nuclei and isolated chromatin. 12 56

Neurospora crassa chromatin isolated by a rapid method minimizing proteolytic degradation contains approximately one weight of acid-extractable basic protein per weight of DNA. This basic protein consists of five major polypeptide species which are similar in size to the histone proteins of higher eukaryotes and are present in approximately the same molar ratios. These five polypeptides have been purified by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Their electrophoretic mobilities in polyacrylamide gels and their amino acid compositions indicate that they are histones homologous, although not identical, to the H1, H2A, H2B, H3, and H4 histones of mammals. The first 3 residues in the amino acid sequence of Neurospora H3 histone are identical to the first 3 residues in calf and pea H3; Neurospora H1, H2A, and H4 histones have blocked NH2 termini, like their mammalian counterparts. The finding of recognizable H1, H2A, H2B, H3, and H4 histones in Neurospora extends the range of eukaryotes now shown to contain a full complement of these strongly conserved chromosomal proteins, and supports the view that histones became involved in chromosome structure at a very early point in the evolution of eukaryotes.
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PMID:Histones of Neurospora crassa. 13 44

Reconstituted complexes of DNA with histone were prepared by salt-and-urea step gradient dialysis. The DNA was complexed with histone H1, with the combination of the other four histones H2A, H2B, H3 and H4, and with whole histones. These DNA-histone complexes were purified by Bio-Gel column chromatography, and the weight ratio of histone-to-DNA was determined in each complex. The thermal denaturation profile and nuclease digestion pattern of DNA-histone H2A, H2B, H3 and H4 complex were compatible with those of the polynucleosome structure of chromatin. The template activities for transcription were compared in these DNA-histone complexes by separately measuring initiation reaction and chain elongation. The binding of histone H1 to DNA strongly inhibited the initiation, while the binding of the combination of the other four histones to DNA partially inhibited the initiation and chain elongation. The binding characteristics are discussed with regard to the role of histone H1 and the other four histones in chromatin structure and template activity.
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PMID:Thermal denaturation and template activities of reconstituted DNA-histone complexes. 14

Administration of 6-aminonicotinamide (6-AN) to rats leads to an opposite effect on the rate at which [3H]UMP is incorporated in vitro into nuclear cerebral neuronal and glial RNA. The inhibition of glial RNA synthesis is temporarily accompanied by both a reduction of the number of RNA initiation sites on glial chromatin and a reduction of [3H]acetate uptake into glial chromatin-bound histones mainly as regards the fraction H2B, H3 and H4. The slight stimulation of neuronal RNA synthesis 6 hours after 6-AN seemed to be caused exclusively by a less steric restriction of neuronal chromatin, whereas the more pronounced stimulation at 24 hours may be related to both a higher activity and/or amount of endogenous neuronal RNA polymerases and an increase in the total number of RNA initiation sites present on the neuronal chromatin. The increase in the total number of neuronal RNA initiation sites is closely parallel with a higher degree of acetylation of neuronal chromatin-bound histone fractions. The 6-AN-induced variations of glial and neuronal in vitro RNA synthesis are discussed in correlation with the neurotoxic action of 6-AN in vivo.
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PMID:Repression of glial RNA transcription during the development of 6-aminonic-otinamide (6-AN)-induced acute gliopathy. 14 38


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