Our structura, as described, is an open one. .There is room between the pair of polynucleotide chains (see Fig. 2) for a polypeptide chain to wind around the same helical axie. It may be signiFicant that the distance between adjacent phosphorus stomas, 7.1 A. is close to the repeat of a fully extended polypeptide chain. We think it probable that in the sperm head
and in artificial nucleoproteins, the polypeptide chain occupies this position. The relative weakness of the second layer-line in the published X-ray is crudely compatible with such an idea. The funotion of the protein might with be to control the coiling and uncoiling. to assist in holding a single polynucleotide chain in a helical configuration, or some other non-specific function.