Figure 1

Schematic illustration of proteins used as targeting vehicles for molecular imaging. (A) Structures of an IgG monoclonal antibody sized relative to a DARPin G3. (B) Four DARPin G3 variants having histidine-containing tags at N-terminus or C-terminus were used in this study. Illustrations were taken from Research Collaboratory for Structural Bioinformatics Protein Data Bank: 1IGT (antibody), 2JAB (DARPin).