The structure and properties of histone F2a comprising the heterologous group F2a₁and F2a₂studied by¹³C nuclear magnetic resonance

(13)C n.m.r. spectra have been obtained for aqueous solutions of histones F2a(1) and F2a(2), for the group F2a, for the appropriate amino acid mixturesand for the corresponding hydrolysates. These, when compared with computer simulated spectra give good agreement for secondary structure with that calculated from the known primary structure of the proteins. Evidence based on the spectra obtained at various salt concentrations leads to the conclusion that F2a is not a simple mixture but an interacting heterologous group of histones F2a(1) and F2a(2).