Human Growth Hormone This protein is a bundle of alpha-helices. Notice the helices are packed at different angles.
To see the packing, in the Menu, go to Style-> Scheme-> CPK Spacefill.
de Vos, A. M., Ultsch, M., Kossiakoff, A. A.: Human growth hormone and extracellular domain of its receptor: crystal structure of the complex. Science 255 pp. 306 (1992)
(PubMed)