Fig. 2.

Structure of the phage T4 LTF tip. a Side view of a ribbon representation of the gp37 trimer fragment containing the D10 and D11 domains. The three chains of the protein homo-trimer are in green, red, and blue, respectively. The iron ions are shown as orange balls, and the histidine side chains coordinating them are visualized. Residues forming the approximate domain boundaries are labeled. b End-on view of the receptor-binding head domain in which the interweaving of the three chains is clearly visible. Molecular graphics images were produced using the UCSF Chimera package from the Resource for Biocomputing, Visualization, and Informatics at the University of California, San Francisco (supported by NIH P41 RR-01081) (Pettersen et al. 2004)