FIGURE 5. a, Topology of 
-chain (green) and 
-chain (red) C-terminal domains.
From the following article:
Crystal structures of fragment D from human fibrinogen and its crosslinked counterpart from fibrin
Glen Spraggon, Stephen J. Everse and Russell F. Doolittle
Nature 389, 455-462(2 October 1997)
doi:10.1038/38947
The first residue in each segment of secondary structure is numbered. b, Stereo depiction of superposed C
backbone structures from globular portions of 
-chains (green) and 
-chains (red); the numbers on the strands and letters on the helices correspond to the secondary structure designations in Fig. 4. c, GRASP representation of binding cavities of -chains (left) and -chains (right) showing charge distribution; red, negatively charged; blue, positively charged47. Domains have been reorientated to show equivalent projections.
