Complexes of histone F1 with DNA in 0.15M NaCl. Circular dichroism and structure of the complexes

Abstract

SynopsisConditions were studied under which aggregated complexes of histone F1 with DNA display a circular dichroic spectrum of nonconservat.ive type characterized by two intense negative maxima a t 269 nm and 209 nm. It was found that the intensity of the longwave band depends directly on the content of guanine plus cytosine and inversely on the molecular weight of DNA. The same type of dependence was found for DNA's of eukaryotic and bacterial origin. It appears that the formation of the nonconservative spectrum which can be ascribed to a certain structural form of DNA is caused by orientation of the DNA molecules in the aggregated complex and by specific interactions of the bases of the guanine-cytosine pair. The possible mechanism of formation of nonconservative dichroic spectrum is discussed with respect to special properties of guanine.

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

“…These results, along with those obtained using DNA's sonicated for different times, show that lowering the molecular weight of the DNA leads to the formation of a greater degree of asymmetry in the con~plex and that a point can be reached beyond which further sonication or lowering of the molecular weight results in the generation of less order in the system. These results are very similar to those obtained with polyethylene oxide solutions of DNA (14) and with histone H-1, DNA complexes (25).…”

“…This characteristic cd spectrum is also produced when D N A is dissolved in water soluble organic polymers, such as polyethylene oxide (PEO) (8)(9)(10)(11)(12)(13)(14). It is also found in dehydrated films of DNA (15), in con~plexes of DNA with several random and sequential lysine-containing polypeptides (i6-221, and in complexes of histone H-1 (F-1) with D N A (23)(24)(25)(26), This characteristic cd spectrum has beer! said to be produced by $-state DNA (8).…”

Salt-induced conformational changes of poly(dA-dT)

“…More or less perfect mirror inversions of the CD spectra of native DNA (especially in the long-wavelength spectral region) were observed under many different conditions (e.g., In water-poly(othylone glycol) (18), water-poly(othylone oxide) (19). or water-methanol (16) mixtures, in very high LiCl concentrations (20), and in complexes of DNA with histones (21,22). poly-L-lysine (23), or poly-L-histidine (24)).…”

Fourier transform infrared/vibrational circular dichroism spectroscopy as an informative tool for the investigation of large supramolecular complexes of biological macromolecules

“…These negative features of the spectra resemble those of the DNA-H1 complexes, 44 which were different from the positive spectra induced by HMGB1-DNA interactions. 12 According to earlier studies, 45 the sign of the bands in the ECD spectra of DNA might differ depending on the charge of the polymer participating in the interaction with DNA.…”