Dykes G, Crepeau R H, Edelstein S J
Nature. 1978 Apr 6;272(5653):506-10. doi: 10.1038/272506a0.
Three-dimensional reconstruction of electron micrographs of the 20-nm diameter fibres of HbS reveals an inner helical core of four strands surrounded by an outer helix of 10 strands to give a total of 14 strands. The strands are arranged with roughly hexagonal packing to produce an unusual helical structure which features a variety of intermolecular contacts and a non-circular cross section.
