title: Micro-environment of the H3-H3 contact region of a nucleosome core particle, as revealed by a lifetime measurement of a fluorescent probe.
abstract: A sample of fluorescently-labeled nucleosome core particles was prepared by combining N-(3-pyrene)-maleimide to each of the two cysteine residues of the two H3 histones in the chicken erythrocyte nucleosome core particle, by a method previously reported by Zama et al. (Nucl. Acids Res. 5, 3881 (1978)). The fluorescence spectra and fluorescence lifetime of the sample in solvents with various Na+ concentrations have been examined. Three different types of micro-environment of the fluorescent probe have been found: (i) emits a pyrene dimer fluorescence at 460 nm, (ii) emits a pyrene monomer fluorescence with a long (75-65 ns) lifetime, and (iii) emits a pyrene monomer fluorescence with a short (5-15 ns) lifetime. The manner of dislocation of the two H3 subunits from each other in each of the solutions with different salt concentrations was discussed.
mesh_terms: D000818:Animals; D002645:Chickens; D004247:DNA; D004912:Erythrocytes / Q000378:metabolism; D005456:Fluorescent Dyes; D006657:Histones / Q000097:blood*; D008301:Maleimides; D009707:Nucleosomes / Q000378:metabolism* / Q000648:ultrastructure; D009994:Osmolar Concentration; D012964:Sodium; D013050:Spectrometry, Fluorescence
chemical_list: D005456:Fluorescent Dyes; D006657:Histones; D008301:Maleimides; D009707:Nucleosomes; D004247:DNA; D012964:Sodium; C003944:N-(3-pyrene)maleimide