Online tutorial on DNA structure
Click the link below to find an interesting tutorial using animations in Jmol to explore the structure of DNA:
http://www.umass.edu/molvis/tutorials/dna/
CIF Files
CIF files contain crystallographic information, allowing you to electronically manipulate three dimensional structures. Download the CIF data files and open them in a compatible program, such as Mercury. These two files relate to figure 6.20 and figure 6.21, on page 144 in Foundations of Molecular Structure Determination 2e.
duckett2e_cif.zip
Note that Mercury software can be downloaded for free here:
http://www.ccdc.cam.ac.uk/Solutions/FreeSoftware/Pages/FreeMercury.aspx
Further information about angiotensin
The structure of angiotensin II:
Click the below link to view 2D and rotatable 3D versions of angiotensin II:
http://www.chemspider.com/Chemical-Structure.150504.html
To access a paper comparing the structures of angiotensin I and II:
http://onlinelibrary.wiley.com/doi/10.1046/j.1432-1033.2003.03573.x/full