International
Tables for Crystallography Volume F Crystallography of biological macromolecules Edited by M. G. Rossmann and E. Arnold © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. F. ch. 1.2, p. 7
Figure 1.2.5.2
aDepartment of Biological Sciences, Purdue University, West Lafayette, IN 47907-1392, USA |
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Figure 1.2.5.2
Cylindrical sections through a helical segment of a myoglobin polypeptide chain. (a) The density in a cylindrical mantle of 1.95 Å radius, corresponding to the mean radius of the main-chain atoms in an α-helix. The calculated atomic positions of the α-helix are superimposed and roughly correspond to the density peaks. (b) The density at the radius of the β-carbon atoms; the positions of the β-carbon atoms calculated for a right-handed α-helix are marked by the superimposed grid (Kendrew & Watson, unpublished). Reprinted with permission from Perutz (1962). Copyright (1962) Elsevier Publishing Co. |