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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

The conformational properties of two non-histone chromosomal proteins (high-mobility-group proteins 1 and 2) have been studied by spectroscopic methods. The interaction of high-mobility-group protein 1 with DNA has also been studied. 1. Circular dichroism results indicate that in the presence of salt both proteins are 40-50% helical between pH 1 and 9. Above pH 9 denaturation takes place. In the absence of salt the proteins denature below pH 4. 2. Nuclear magnetic resonance spectra show the presence of ring-current shifted peaks and perturbed aromatic resonances, demonstrating that the helix formation is accompanied by specific tertiary folding. 3. Nuclear magnetic resonance spectra of compelxes between high mobility group protein 1 and DNA demonstrate that a low ionic strength a portion of the molecule rich in lysine and containing all the aromatic residues is bound to DNA, whilst a more acidic region of the chain remains free from the DNA.
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PMID:Conformational studies of two non-histone chromosomal proteins and their interactions with DNA. 0 4

Psoriatic scale proteases were found to be extracted effectively in salt solution (1 mol/l) containing Triton X-100 (5 g/l). The extraction in dilute buffer or sucrose yielded low activities. The acid (0.25 N H2SO4) and KSCN (2 mol/l) solutions effectively extracted plasminogen activator. Fibrinolysin was most active in salt (1 mol/l KCl) and in KSCN (2 mol/l) extracts. Psoriatic scale proteases were fractionated by Sephadex G-100 gel filtration and further by DEAE cellulose chromatography. Five different enzyme preparations were obtained. The first preparation, resembling cathepsin D, effectively hydrolysed hemoglobin at pH 3.5 and casein at pH 5.8 and was insensitive to protease modifiers. The second preparation effectively hydrolysed trypsin substrates (AGLME, TAME, BAEE and BANA) and also histone and casein at pH 7.2 and was inhibited by protease inhibitors, TLCK and E-600. The third preparation hydrolysed histone and casein at pH 10.2 and was effectively inhibited by E-600 and partially by protease inhibitors and TPCK. The fourth preparation, resembling cathepsin B1, hydrolysed BANA and BAEE at pH 5.8 and was activated by SH-reagents and EDTA. The fifth enzyme preparation hydrolysed ATEE and was inhibited by E-600 and TPCK. Plasminogen activator was found mainly in the second enzyme preparation and fibrinolysin activity in the third and fifth enzyme preparations. The second, third and fifth enzyme preparations were different from the enzymes found in healthy human skin. The proteases of psoriatic scale resemble those of tissue and cell cultures undergoing rapid cell division. The possible role of proteases in the increased cell division in psoriasis plaque is discussed.
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PMID:Human skin proteases. Fractionation of psoriasis scale proteases and separation of a plasminogen activator and a histone hydrolysing protease. 0 31

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

Crosslinking of DNA fibers by histone H1 or phosphorylated on Ser-37 histone H1, and by the individual fragments of the H1 polypeptide chain was studied by the method of turbidimetry. The dependence of the turbidity of DNA-protein complexes on the ionic strength in solution suggests that the condensation of H1.DNA complexes in vitro is apparently due to both specific histone-DNA interactions with the contribution of hydrogen and/or hydrophobic bonds and the formation of polycationic "bridges" fastening the DNA fibers. The effectiveness of the condensation is postulated to be a function of a proportion between the two mechanisms which in turn can be controlled by slight changes in ionic surroundings. The sharp dependence of shrinkage of H1.DNA complexes on ionic strength at "physiological" salt concentrations could provide a mechanism to regulate density and consequently the total activity of chromatin in the cell nuclei. The phosphorylation of histone H1 on Ser-37 by a specific histone kinase does not noticeably affect the pattern of DNA crosslinking by the H1.
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PMID:Histone H1--DNA interaction. On the mechanism of DNA strands crosslinking by histone H1. 2 66

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

Several proteinases hydrolyzing histone and caseine in neutral media were obtained by Sephadex G-100 fractionation of water and salt (1 M KCl) extracts of human spleen. The level of the activity of proteinases in the extracts was very low as a result of the presence of an inhibitor. Neutral proteinases were found in two protein fractions. The "high-molecular-weight-" proteinases were inhibited by DFP and therefore they were attributed to a group of serine proteinases. The "low-molecular-weight" fraction contained neutral SH-dependent proteinase(s) and DFP-inhibited enzymes. In this fraction, the kininogenase activity and the hydrolysis of Boc-1-ananine p-nitrophenyl ester, N-benzoyl-L-tryosine ethyl ester and N-benzoyl-DL-arginine p-nitroanilide were observed.
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PMID:[Characterization of neutral proteinases from human spleen]. 4 6

Experiments on isolated mouse liver muclei involving enzyme digestion, the crosslinking of amino groups and alkaline hydrolysis demonstrate that bismuth binds to nucleoproteins through amino and phosphate groups. Analysis of the nucleoproteins extracted with salt and acid solutions in conjunction with bismuth staining after these treatments suggests that: (1) a bismuth amino group interaction occurs on ribonucleo-protein particles, histones and perhaps some non-histone chromosomal proteins, and (2) bismuth phosphate binding is specific for one, or all, of three distinct species of non-histone proteins. These results suggest that histones not tightly bound to DNA through their amino groups are present on interchromatin granules, the presumed transcriptionally active regions of chromatin. Phosphorylated non-histone proteins are also localized at these sites. Staining with heavy metals such as bismuth may be the best method for high resolution localization of nucleoproteins involved with regulating gene activity and maintaining chromatin structure.
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PMID:Nucleoprotein localization by bismuth staining. 7 36

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

The isolated nuclei of wheat embryo possess the ATPase activity. The addition of Mg2+ and Ca2+ significantly increases the activities of nuclear ATPases, whereas Hg2+, Cu2+ and Mn2+ inhibit the activity. The activating effect of Mg2+ is enhanced by an addition of Na and K ions. The activity of wheat embryo nuclear Mg-ATPase is higher than its Ca-ATPase activity; both ATPases also differ in their pH optima. Separation of total nuclear protein according to the solubility of its individual protein components in wheat and strong salt solutions, using the detergents, as well as ammonium sulfate precipitation and dialysis do not result in separation of Mg-activated and Ca-activated ATPases, although their levels of activities and ratios change in the course of fractionation. The Mg- and Ca-ATPase activities of the wheat embryo nuclei were found in the nuclear fraction of albumin, in nonhistone proteins and nuclear membranes. In the albumin nuclear fraction and subfractions of non-histone proteins the higher level of activity is observed in Ca-ATPase, whereas in the nuclei and soluble fractions of residual proteins in Mg-ATPase.
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PMID:[Properties and localization of Mg- and Ca-ATpase activities in wheat embryo cell nuclei]. 14 25


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