Effect of formaldehyde on the circular dichroism of chicken erythrocyte chromatin

Senior, Marilyn B.; Olins, Donald E.

doi:10.1021/bi00686a007

Cited by 18 publications

(6 citation statements)

References 24 publications

(43 reference statements)

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“…The formatin of crosslinks between histones and DNA results in a conformational change of DNA, which is detectable as a change of positive ellipticity in the region of 250-300 nm. Decrease of positive ellipticity of nucleohistone on reaction with formaldehyde has been reported by Senior and Olins [16], but their results do not agree with our results. They reported that the positive ellipticity above 240 nm progressively decreased with increase in the formaldehyde concentration, finally attaining a negative value with 3 % formaldehyde.…”

Section: Discussioncontrasting

confidence: 99%

Reaction of Formaldehyde with Calf-Thymus Nucleohistone

1979

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The reactions of formaldehyde with calf thymus nucleohistone were analyzed in the following ways : measurement with fluorescamine of the decrease in primary amino groups resulting from hydroxymethylation and crosslinking reactions, measurement with dodecylsulphate-gel electrophoresis of formation of histone oligomers, measurement of fixation of histones to the DNA in nucleohistone, and measurement of changes in the circular dichroism spectrum in the region of 250 -300 nm. In the presence of formaldehyde, the primary amino groups of histones decreased very rapidly, attaining an equilibrium within 60 min, and successively intermolecular crosslinks were also formed between histone molecules, the resulting dimers and oligomers being separable by dodecylsulfate-gel electrophoresis. Whereas the fixation reaction proceeded much more slowly. The extent of fixation could be measured more accurately by dodecylsulfate/sucrose centrifugation analysis than by sulfuric acid extraction. After removal of f-ormaldehyde from the reaction mixture, the fraction of masked amino groups decreased, perhaps due to the reverse reaction, but the extent of fixation of histones continued to increase with time. No specificity was observed among five molecular species of histones in the fixation reaction. With increase in formaldehyde concentration, the ellipticity of nucleohistone decreased to a minimum with about 0.4 % formaldehyde, and then increased.Formaldehyde is known to bind to various groups of proteins, including primary amino and imidazole groups [l -31. There formaldehyde has both monofunctional and bifunctional actions. Many studies on the interactions of formaldehyde with nucleic acids have also shown that formaldehyde can react with both the exocyclic amino groups and endocyclic imino groups of DNA bases [4 -61.Formaldehyde has recently been used in physical characterization of chromatin [7 -lo]. The mechanism of the reaction between formaldehyde and nucleohistone has been reported by several workers [ l l -161. In this process formaldehyde reacts with both histones and DNA, acting as a fixative. The treatment of nucleohistone with formaldehyde results in complex in which protein-DNA interaction is no longer ionic as it is in native nucleohistone. The treated complexes are not dissociated either by 4 M CsCl or 0.1 M HzS04. In this work, we investigated the interactions of formaldehyde with calf thymus nucleohistone in following ways : namely by measuring decreases in primary amino groups of histone, fixation of histones to DNA, and changes of the circular dichroism spectrum in the Abbreviation. CD, circular dichroism region of 250 -300 nm, due to conformational changes of the DNA in chromatin. MATERIALS AND METHODS Preparation of NucleohistoneNucleohistone was prepared from 20 -40 g of frozen calf thymus glands by a modification of the method of Zubay and Doty [17]. Thus 20-40g of frozen calf thymus glands were minced with scissors and then homogenized in 300 ml of standard solvent (0.14 M NaC1, 0.01 M EDTA pH 7.0) with a homog...

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Section: Discussioncontrasting

confidence: 99%

Reaction of Formaldehyde with Calf-Thymus Nucleohistone

1979

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“…Figure 5a shows CD spectrum of native chromatin and that of chromatin treated with formaldehyde either for 1 or 24 h. Formaldehyde treatment causes a permanent decrease and red shift of the positive CD band near 275 nm and a slight decrease in the negative CD band near 220 nm, changes which occur mostly during the first hour of fixation. These results confirm the original observations of Senior and Olins (1975)…”

Section: Resultssupporting

confidence: 92%

Histone redistribution and conformational effect on chromatin induced by formaldehyde

Polacow¹,

Cabasso²,

Li³

1976

Biochemistry

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Histone redistributions between endogenous DNA in calf thymus chromatin and exogenous DNA from Clostridium perfringens (69% A + T) or from Micrococcus luteus (30% A + T) induced by 0.6 M NaCl or by 2% formaldehyde were studied by thermal denaturation. The observed redistribution occurred on histone Hl when the exogenous DNA was (A + T)-richer than the DNA in chromatin, and when the mixture was exposed to 0.6 M NaCl or formaldehyde. When a (G + C)-richer DNA was added as the acceptor for histones, no substantial transfer of histones from chromatin DNA to exogenous DNA was found. Thus the activation energy of histone dissociation from chromatin DNA seems to be substantially lowered by 0.6 M NaCl or formaldehyde such that histones (mostly histone Hl) can be dissociated and bind the (A + T)-richer DNA and form a more stable complex. It is suggested that the formaldehyde effect on histones may be due to the loss of positive charges on lysine and arginin residues (probably more on lysine than on arginine) in histones after their rapid reaction with formaldehyde. Formaldehyde treatment of chromatin also distorts the DNA conformation, as revealed by circular dichroism (CD) studies. This structural effect occurs mainly on those base pairs bound by histones other than Hl, or within the chromatin subunit. Histone redistribution is treated as a thermodynamic phenomenon of histone binding to DNA. The validity of using formaldehyde to study chromatin structure is discussed.

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“…Only small changes (< 105;;) in the cd spectrum ellipticity at 275 nm bere noted. This is unlike the observations made on chromation in solution (28).…”

Section: Electroiz Microscopycontrasting

confidence: 93%

Water-soluble lysine-containing polypeptides. III. Sequential lysine-glycine polypeptides. A circular dichroism and electron microscopy study of annealed complexes with DNA, sonicated DNA, and denatured DNA

Kielland¹,

Williams²

1976

Can. J. Chem.

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. Can. J. Cheni. 54, 3884 (1976). Circular dichroic spectra, turbidity n~easuren~ents, and electron micrographs have been taken of annealled complexes of native, sonicated. and denat~~red DNA's in association with several sequential lysine-glycine copolypeptides. The results indicate that: (I) the n~olecular weigh: and strandedness of the DNA influences not only the assymmetric orgaiiization of the DNA in the complexes but also the size and shape of the complexes formed; (2) the hydrophobic nature (or sequence) of the polypeptide influences the shape of the complexes formed.SANDRA L. KIELLAND et Ross E. WILLIA~IS. Can. J. Chem. 54, 3884 (1976). Des spectres du dichroi'sme circulaire, des rnesures de turbidit6 ansi que des micrographics electroniques cle complexes entre 1'ADN (nature!, trait6 aux ultrasons et denature) et quelques poljpeptides lysine-glycine de sequence regulikre ont Ct C pris. Les rCsultats niontrent que: (I) la presence de cleux chaines associees dans la molCcule de 1'ADN ainsi que le poids mol6cu-iaire de celle-ci influence non seulenient l'organisation asymetrique de 1'ADN dans les complexes mais aussi la grandeur et la forme de ces derniers; (2) la forme des complexes dCpend de la nature hydrophobique (ou i6quence) du polypeptide.

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Effect of formaldehyde on the circular dichroism of chicken erythrocyte chromatin

Cited by 18 publications

References 24 publications

Reaction of Formaldehyde with Calf-Thymus Nucleohistone

Reaction of Formaldehyde with Calf-Thymus Nucleohistone

Histone redistribution and conformational effect on chromatin induced by formaldehyde

Water-soluble lysine-containing polypeptides. III. Sequential lysine-glycine polypeptides. A circular dichroism and electron microscopy study of annealed complexes with DNA, sonicated DNA, and denatured DNA

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