[Structure of chromosomal deoxyribonucleoproteins. X. Investigation of protein organization in chromosomal subunits with the aid of bifunctional agents].

Chromosomal proteins were treated with imido esters or with formaldehyde. Histones and their oligomers were then obtained by acid extraction and analyzed by two-dimensional gel electrophoresis. We discovered a nonameric histone oligomer in which histone H1 complexes with the octamer of small histones. In this complex, H1 interacts preferentially with H2a and H3. One can suppose from these experiments that histone H1 has close contacts with core histones. Another conclusion from the results obtained is that the structure of the nucleosome core is different in H1-containing mononucleosomes and in core particles. Thus, histone H1 is an important component of the nucleosomal protein complex and its presence is necessary for supporting the native compact state of the nucleosomal core.