Nitration of the tyrosine in histone F1 in salt solutions and in F1-polyanion complexes.
The reaction of histone F1 with tetranitromethane was used to study the environment of the single tyrosine residue in the molecule. It was found that at a 10-fold molar excess of tetranitromethane over tyrosine approx. 40 min were needed to convert 85% of the tyrosine residues to nitrotyrosine. The rate and extent of nitration of F1 in dilute salt solutions was used as a reference against which the rate and extent of nitration under conditions known to affect the conformation of F1 was measured. In 1.0 M NaCl solutions the rate of nitration decreased, suggesting that the presence of salt may cause a conformational change in the tyrosine containing region of the histone. When the histone is complexed with polyanions such as DNA, RNA or poly-L-glutamic acid the accessibility of the tyrosine to nitration is markedly reduced. The results indicate that upon association with polyanions the non-cationic, tyrosine-containing, region in F1 undergoes a conformational change or alternatively, this tyrosine containing region is tightly associated with the polyanion.
Bustin
M
M
Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel.
D000818:Animals; D002417:Cattle; D004247:DNA / Q000737:chemistry* / Q000302:isolation & purification; D006657:Histones / Q000737:chemistry* / Q000302:isolation & purification; D007700:Kinetics; D009691:Nucleic Acid Denaturation; D012313:RNA / Q000737:chemistry; D012967:Sodium Dodecyl Sulfate; D013053:Spectrophotometry; D013774:Tetranitromethane; D013950:Thymus Gland / Q000737:chemistry; D014443:Tyrosine
D006657:Histones; D012967:Sodium Dodecyl Sulfate; D014443:Tyrosine; D012313:RNA; D004247:DNA; D013774:Tetranitromethane