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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Study is presented of the effect of noradrenaline on thermic denaturation of DNA-total histone complexes within the range of protein concentrations which corresponds to c1/c2 0-1.7 in solutions of 10(-3) M Na+ ionic strength (c1 and c2 being the weight concentrations of protein and nucleic acid, respectively). Denaturation of these systems has been found to be strongly affected by bivalent metals contained in DNA samples. Their presence accounts for the high temperature and wide melting range of DNA and diminution of the latter with an increase of the protein concentration in DNA-histone complexes. The denaturation parametres obtained for the studied systems are in fair agreement with predictions from the clip thermodynamic theory. Noradrenaline is shown to be capable of destabilizing DNA-total histon complexes. This is due to the inactivation of bivalent metals bound with DNA by noradrenaline. It is also suggested that noradrenaline does not weaken the histone binding with a nucleic acid.
Mol Biol (Mosk)
PMID:[Melting of DNA-total histone complexes in the presence of noradrenaline]. 105 66

The non-histone chromatin proteins (NHP) were isolated by a modified Wang technique. NHP were easily dissoluble in solutions of a physiological ionic strength within a wide pH range. NHP were subdivided into 18 zones by analytical polyacrylamide gel electrophoresis. NHP have molecular weights within the range 15,000 greater than 200,000. A part of NHP showed similar molecular weight but different values of molecular charge. NHP were separated by a gel filtration into 6 fractions. Two fractions were individual proteins. The great bulk of NHP has a molecular weight less than 40,000, and 6-6.5% of NHP-more than 100,000. The fractions different from each other in a specific UV-absorbtion, fluorescence and circular dichroism. The nhp fraction of a smaller molecular weight has a smaller content of alpha-helix (8%) and the greatest polarity of the environment of tryptophan residues; the molecules of this fraction may have a loose tertial structure. Other NHP have 15-24% of alpha-helix and possibly have compact globular sites.
Mol Biol (Mosk)
PMID:[Partial fractionation and physico-chemical properties of non-histone chromatin proteins]. 105 76

Chromatin fractions (DNA, histones and non-histone chromosomal proteins NHCP) have been isolated from human peripheral B and T lymphocytes using different methods and analyzed in order to identify their lipid content. While DNA and histone fractions do not reveal the presence of lipids, a 2% of phospholipids is present in the NHCP fraction. The phospholipids associated with NHCP present a constant relative ratio among sphingomyelin, phosphatidyl-choline and phosphatidyl-ethanolamine both in B and T lymphocytes, whichever are the extraction procedures employed. These findings are related to the possible dereprssive role of phospholipids on DNA-dependent RNA synthesis.
Mol Cell Biochem 1976 Aug 30
PMID:Phospholipids bound to acidic nuclear proteins in human B and T lymphocytes. 108 12

The mode of reassociation of Ehrlich ascites histones and non-histone proteins during chromatin reconstitution was studied by sodium dodecyl sulfate polyacryl-amide gel electrophoresis. In the procedure of Bekhor et al. (I. Bekhor, G. M. Kung, and J. Bonner, (1969), J. Mol. Biol. 39, 351) most of histones and non-histone proteins reassociate with DNA in the last dialysis step of the dissociated chromatin, that is the dialysis of the chromatin in 0.4 M NaCl-5 M urea against a dilute buffer. The reassociation of histones and non-histone proteins with DNA is more gradual in the procedure of L. Kleiman and R.-C. C. Huang [(1972), J. Mol. Biol. 64, 1]. However, in both procedures the bulk of the Ehrlich ascites non-histone proteins reassociate with DNA after the binding of histones to DNA. There are small amounts of non-histone proteins which reassociate with DNA before and at the same time as histones reassociate with DNA.
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PMID:Reconstitution of chromatin: mode of reassociation of chromosomal proteins. 112 76

A description is provided for the effects of various concentrations of NaCl, MgC12, and urea on the precipitation of native and denatured DNA by histones. The solubility of complexes between total histones and fractions F1, F2a, F2b, and F3 with denatured and partially denatured DNA was greater than that of the complexes between histones and native DNA. The complexes formed between histones and denatured DNA were soluble in excess histones, unlike those formed between histones and native DNA. Electrophoresis of the individual histone fractions through a polyacrylamide gel layer containing DNA led to the determination of the amount of histones bound to native and denatured DNA under conditions of saturation (0.04 ionic strength). It was established that 1 mug of native DNA binds 2.4, 2.8, and 2.5 mug of histones F1, F2a, F2b and F3, respectively. The denatured DNA binds 1.4-1.5 times less of each histone fraction than does native DNA, but the binding seems stronger. It has been demonstrated that the histones inhibit to a lesser extent the template activity of denatured and partially denatured (about 5% disruption of hydrogen bonds) DNA in comparison with native DNA in an RNA polymerase system. It has been suggested that the properties of the complexes formed between histones and denatured or partially denatured DNA, may underlie the control mechanism for genome activity in the cells of higher organisms.
Mol Biol 1975 Jan
PMID:The interaction of histones with native and denatured DNA. 112 1

Unsheared chromatin isolated from sea urchin embryos was submitted to buoyant density centrifugation in sucrose-glucose gradients. The main peak of blastula chromatin was at a density position of 1.299 plus or minus 0.028 plus or minus 0.009 g ml -minus 1 whereas at gastrula stage a shift to a lower bouoyant density position of (1.276 plus or minus 0.021 plus or minus 0.007 g ml minus 1) was observed. Besides the main peak, a small band with a density of 1.18 g ml minus 1 was noticed. The lighter fraction differed from the heavy one in a higher histone to DNA ratio, a lower proportion of the F-1 histone, and a lower nonhistone to DNA ratio. The most pronounced developmental alterations of proteins were observed at the level of nonhistone protein patterns of the light fractions.
Mol Biol Rep 1975 Mar
PMID:Buoyant density centrifugation of sea urchin embryo chromatin on sucrose-glucose gradient. 112 15

A new model for the fine structure of the chromatin subunit (or 'nucleosome') is proposed. The model is based on previous experimental findings [1-14] and on two new suggestions, namely: (1) Eight histones form a toroidal-shaped histone coe of nucleosome and are arranged in the following ciruclar sequence: (see article). (2) DNA is 'kinked' around a toroidal-shaped histone core in a 'solenoid-like' mode, each kink occurring every 10 base pairs along DNA. The electron microscopic evidence for a toroidal shape of the nucleosome is described in the preceding paper [13]. The possibility of the existence of kinks in the DNA double helix was considered recently by Crick and Klug [14]. The proposed model of the nucleosome, being more detailed than earlier models permits us to explain in direct structural terms the yet unordered set of data bearing on the pattern of histone-histone interactions in chromatin, the results of a mild deoxyribonuclease digestion of DNA within the nucleosomal particle and also the quantitative data on the unwinding of the DNA duplex upon formation of the nucleosome.
Mol Biol Rep 1975 Oct
PMID:Studies on chromatin. V. A model for the structure of chromatin subunit. 119 13

A planar texture in dried film samples of DNP was found by X-ray study. Axes of DNA macromolecules are located in the film plane and the 77 A reflection is directed along this axis. Periodic structures corresponding to 55 and 34 A are packed parallel to the film plane. The results obtained do not contradict with a supercoil DNP model, however they all allow other possible packing models of DNP molecules, in particular, histone layers alternating with DNA layers in oriented films.
Mol Biol (Mosk)
PMID:[Application of x-ray analysis for the study of the orientation in DNP films]. 121 1

The interaction of different preparations of chromatin non-histone proteins (NHP) isolated from rat liver and thymus with homologous and heterologous DNA was studied by a membrane filter technique. All the NHP preparations studied form complexes with DNA in 0.02 tris-HCl (pH 7.5)--3 mM MgCl2. Denatured DNA binds NHP more effectively than native NDA. The largest part of NHP which interacts with DNA is bound to the latter non-specifically. A small part of NHP interacts specifically with homologous native DNA in 5 M urea. Specific binding of NHP to denaturate DNA is shown both in the presence of urea and in its absence. The data obtained are discussed in the light of a possible role of NHP in the specific regulation of transcription process.
Mol Biol (Mosk)
PMID:[Interaction of chromatin non-histone proteins with homologous and heterologous DNA]. 121 6

The amount of individual fractions in the whole histone isolated from the blood of hen, frog (Rana ridibunda), bream (Abramis brama), from rat thymus and from the locust (Schistocerca gregaris) was studied quantitatively. It is shown that the ratios between fractions F2a1, F2b, F2a2 and F3 are fixed. The share of each fraction in the sum of fractions F2a1, F2b, F2a2, F3 was found to be approximately 22.5, 30.5, 21.0 and 26.0 per cent, respectively. The share of the fraction F1 can variate within a rather wide range.
Mol Biol (Mosk)
PMID:[A study of ratios between histone fractions]. 121 8


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