Open AccessFluorescently Labelled Histones as Probes of Nucleosome Structure
Author(s) -
LEWIS Peter N.
Publication year - 1979
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1979.tb13259.x
Subject(s) - nucleosome , histone , chemistry , histone h4 , dna , histone octamer , fluorescence , biophysics , biochemistry , biology , physics , quantum mechanics
A fluorescent derivative of calf thymus histone H4 has been prepared by the reaction of methionine‐84 with N ‐(iodoacetylaminoethyl)8‐naphthylamine‐1‐sulfonic acid at pH 2.4 in 8 M urea. The preparation and characterization of this labelled histone is described. Fluorescence emission measurements indicate that the label onH4 undergoes a 3–5‐fold increase in emission intensity when H4 self‐interacts or binds to DNA alone or is incorporated in a synthetic nucleosome. The changes observed are consistent with the formation of varied apolar environments around methionine‐84, due most likely to histone‐histone rather than histone‐DNA interactions. Preliminary experiments indicate that the precise emission intensity of labelled H4 in the nucleosome is quite sensitive to conditions of ionic strength and histone integrity.