Basic polypeptides as models of histones: Synthesis, conformation and interaction with DNA of sequential polypeptides containing lysine, alanine, and proline

Šponar, J.; Štokrová, Š.; Koruna, Ivan; Bláha, K.

doi:10.1135/cccc19741625

Cited by 19 publications

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“…Comparison of the results herein with studies of interactions between DNA and polypeptide containing, in addition to llysine, L-proline, L-alanine, and L-glycine (Sponar et al, 1973(Sponar et al, , 1974 or L-leucine (Ong and Fasman, 1976;Ong et al, 1976) shows the following pattern. If there are long runs or a large fraction of hydrophobic groups, aggregates form with large positive ellipticities at 280 nm.…”

Section: Discussionmentioning

confidence: 58%

“…The complex shows aggregation with visible turbidity, absorption in the ultraviolet at long wavelengths, and a separable precipitate of the complex enriched in poly(L-Lys) with respect to the supernatant (Li et al, 1974c). The large and sharp CD change at [6)280 observed as the salt concentration is decreased is paralleled by the precipitability of the DNA in the complex (Sponar et al, 1974) and therefore probably corresponds to the onset of binding between polypeptide and DNA.…”

Section: Discussionmentioning

confidence: 99%

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Chromatin models. Interactions between DNA and polypeptides containing L-lysine and L-valine: circular dichroism and thermal denaturation studies

Mandel¹,

Fasman²

1976

Biochemistry

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The interaction of calf thymus DNA with statistical copolymers of L-lysine and L-valine [poly(L-Lys100f-Lvalf)] and block copolymers [poly(L-Lys)100f-poly(L-Val)f] were investigated as a function of ionic strength using circular dichroism (CD) spectroscopy. It was found that valine suppresses the ability of the copolymer-DNA complexes to yield a psi-type CD spectra as found for poly(L-Lys)-DNA [Jordan, C.F., Lerman, L.S., and Venable, J.N. (1972), Nature (london), New Biol. 236, 67] and lowers the ionic strength at which CD distortion occurs. Thermal denaturation, simultaneously monitoring 280-nm ellipticity, [theta]280, and hyperchromicity, h280, was carried out on annealed complexes of poly(L-Lys)-DNA, poly(L-Lys84.5-L-Val15.5)-DNA, poly(L-Lys)87.2-poly(L-Val)12.8-DNA, and directly mixed complexes of poly(L-Lys)-DNA, IN 2.5 X 10(-4) MEDTA, pH 7.0 solution. The CD denaturation of uncomplexed DNA at several ionic strengths was also determined to examine pre-melting. Despite the inability of both statistical and block copolymers of L-Lys and L-Val to form psi-type complexes with DNA, they bind as well to DNA as does poly(L-Lys) and give rise to a thermal denaturation pattern showing bound peaks between 90 and 100 degrees C, seen clearly with CD denaturation. The thermal denaturation of mixed and annealed complexes of poly(L-Lys)-DNA shows similar patterns in hyperchromicity changes as a function of temperature but very different CD melts. From the CD melt of annealed poly(L-Lys)-DNA, it appears that aggregation and long-range order of the complex are significant in low salt (2.5 X 10(-4) MEDTA) as well as in 1.0 M NaCl. These studies further illustrate the importance of the nature of nonionic interactions (hydrophobic) between polypeptides and DNA in determining the behavior of their complexes, such as causing condensation into higher order asymmetric structures. In light of these observations, the possible significance to the CD melting of chromatin and the validity of identification of C-form DNA by CD spectroscopy are discussed.

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Section: Discussionmentioning

confidence: 58%

Section: Discussionmentioning

confidence: 99%

Chromatin models. Interactions between DNA and polypeptides containing L-lysine and L-valine: circular dichroism and thermal denaturation studies

Mandel¹,

Fasman²

1976

Biochemistry

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“…l), albeit of slightly reduced intensity at similar lysine/DNA-phosphate ratios. In appearance these spectra were like those seen in unoriented dehydrated films of DNA (31), in complexes formed between DNA and poly-(Lalanyl-L-lysyl-L-proline) (32), in complexes formed between calf thymus DNA and the lysine-rich histone f-1 (33-37) and in complexes of polyethylene oxide or sodium polyacrylate and DNA (38). Poly-(L-lysylglycine) (11) (Fig.…”

Section: Resultsmentioning

confidence: 95%

Water-Soluble Lysine-containing Polypeptides. II. The Interaction of Several Sequential Lysine–Glycine Polypeptides with DNA. A Circular Dichroism Study of DNA Conformation in Annealed Complexes

Williams¹,

Kielland²

1975

Can. J. Chem.

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“…CD spectra of DNA bound by poly(LyS48, His52) calculated from Eq. (3). Complexes made at pH 7.0 but adjusted to and measured at pH 9.2 (---), made and measured at pH 9.2 (--a ) , made and measured at pH 7.0 (-1, made at pH 9.2 but adjusted to and measured at pH 7.0 (---).…”

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confidence: 99%

Interaction between poly(L‐lysine⁴⁸, L‐histidine⁵²) and DNA

Santella

1977

Biopolymers

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SynopsisP o l y ( L y~~~, His52), a random copolypeptide of L-lysine (48%) and L-histidine (52%), was used as a model protein for investigating the effects of protonation on the imidazole group of histidines on protein binding to DNA. The complexes formed between p01y(Lys~~, His5? and DNA were examined using absorbance, circular dichroism (CD), and thermal denaturation. Although increasing pH reduces the charges on histidine side chains in the model protein, the protein still binds the DNA with approximately one positive charge per negative charge in protein-bound regions. Nevertheless, CD and melting properties of poly(Lys4*, His5*)-DNA complexes still depend upon the solution pH which determines the protonation state of imidazole group of histidine side chains. At pH 7.0, the complexes show two characteristic melting bands with a t , (46-51OC) for free base pairs and a t', (94OC) for proteinbound base pairs. The t k of the complexes is reduced to 90°C a t pH 9.2, although a t this pH there is still one lysine per phosphate in protein-bound regions. Presumably, the presence of deprotonated histidine residues destabilizes the native structure of protein-bound DNA. The binding of this model protein to DNA causes a red shift of the crossover point and both a red shift and a reduction of the positive CD band of DNA near 275 nm. This phenomenon is similar to that caused by polylysine binding. These effects, however, are greatly diminished when histidine side chains in the model protein are deprotonated. The structure of already formed poly(Lys4*, H~S~~) -D N A complexes can be perturbed by changing the solution pH. However, the results suggest a readjustment of the complex to accommodate charge interactions rather than a full dissociation of the complex followed by reassociation between the model protein and DNA.

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Basic polypeptides as models of histones: Synthesis, conformation and interaction with DNA of sequential polypeptides containing lysine, alanine, and proline

Cited by 19 publications

References 0 publications

Chromatin models. Interactions between DNA and polypeptides containing L-lysine and L-valine: circular dichroism and thermal denaturation studies

Chromatin models. Interactions between DNA and polypeptides containing L-lysine and L-valine: circular dichroism and thermal denaturation studies

Water-Soluble Lysine-containing Polypeptides. II. The Interaction of Several Sequential Lysine–Glycine Polypeptides with DNA. A Circular Dichroism Study of DNA Conformation in Annealed Complexes

Interaction between poly(L‐lysine⁴⁸, L‐histidine⁵²) and DNA

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Basic polypeptides as models of histones: Synthesis, conformation and interaction with DNA of sequential polypeptides containing lysine, alanine, and proline

Cited by 19 publications

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Chromatin models. Interactions between DNA and polypeptides containing L-lysine and L-valine: circular dichroism and thermal denaturation studies

Chromatin models. Interactions between DNA and polypeptides containing L-lysine and L-valine: circular dichroism and thermal denaturation studies

Water-Soluble Lysine-containing Polypeptides. II. The Interaction of Several Sequential Lysine–Glycine Polypeptides with DNA. A Circular Dichroism Study of DNA Conformation in Annealed Complexes

Interaction between poly(L‐lysine48, L‐histidine52) and DNA

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Interaction between poly(L‐lysine⁴⁸, L‐histidine⁵²) and DNA