THE STRUCTURE OF DUPLEX DNA IN THE NUCLEOSOME CORE PARTICLE - AN ALTERNATIVE MODEL

Many studies indirectly indicate that the conformation of in vivo dupl ex DNA is the double helix. The most direct view, from the X-ray analy sis of the nucleosome core particle, has also been interpreted in term s of the double helix structure. However, an alternative possibility e xists; that the duplex adopts a metastable side-by-side conformation w hich readily converts to the double helix on removal of protein. Evide nce for the existence of this conformation has been obtained from a re analysis of the electron density map for the nucleosome particle.