Rotational dynamics nucleosomes

The rotational dynamics of nucleosomes containing (146 2)-bpDNA bound to core particles was studied by FPA(21,59 ° 235-1 of intercalated ethidium and by TPD(62) of intercalated Methylene Blue. These studies yield strong evidence that DNA wrapped around the histone core particle exhibits... 

Low CM, Drew HR, Waring MJ (1986) Echinomycin and distamycin induce rotation of nucleosome core DNA. Nucleic Acids Res 14(17) 6785-6801 Luger K (2006) Dynamic nucleosomes. Chromosome Res 14(1) 5—16... 

The broad field of nucleic acid structure and dynamics has undergone remarkable development during the past decade. Especially in regard to dynamics, modem fluorescence methods have yielded some of the most important advances. This chapter concerns primarily the application of time-resolved fluorescence techniques to study the dynamics of nucleic acid/dye complexes, and the inferences regarding rotational mobilities, deformation potentials, and alternate structures of nucleic acids that follow from such experiments. Emphasis is mainly on the use of time-resolved fluorescence polarization anisotropy (FPA), although results obtained using other techniques are also noted. This chapter is devoted mainly to free DNAs and tRNAs, but DNAs in nucleosomes, chromatin, viruses, and sperm are also briefly discussed. 

Fig. 7. Cross-linker model for nucleosome arrangement in the chromatin fiber superstructure in the presence (a) or absence (b) of H1/H5, based on data in the literature (see text) and H5-containing mono-nucleosome stem structure in Fig. 3(c). In 3D, the plane of the nucleosomes is expected to rotate more or less regularly around the fiber axis, forming a solenoid-like superstructure. Nucleosomes 1, 2 and 5 are in the open conformation of Fig. 3(a), nucleosomes 4 and 7 in the open conformation of Fig. 2(b), and other nucleosomes in the closed negative (Fig. 2(c)) or positive conformations. Nucleosomes are expected to thermally fiuctuate between the different conformations, within an overall dynamic equilibrium of (ALkn) -l (see text). -I- and - refer to node polarities. (From Fig. 5 in Ref. [28].)...

---