Figure 3

In vitro -binding studies of A38. (a) Dot blot of VACV (VR-1536), non-infective cell culture supernatant (CC) and CMV, followed by incubation of biotin-conjugated A38 in various concentrations and labeling with a streptavidin peroxidase conjugate. (b) Surface Plasmon Resonance measurements (Biacore) of A38. Sequence of injections (injection start): A38 (150 s); VACV (1050 s); 50 mM sodium carbonate (2320 s); 1:10 diluted VACV (4080 s). The overlaid VACV net binding curves are shown on the right hand side. (c) Fluorescence Correlation Spectroscopy (FCS). Normalized autocorrelation functions (ACF) of tetramethylrhodamine isothiocyanate (TMR): free in solution (black), coupled to A38 alone (blue), coupled to A38 with added CMV (brown), coupled to A38 with added VACV (red), and directly coupled to VACV (green). Control experiments with CMV (brown) and 200-nm latex beads (not shown) mixed with TMR-conjugated A38 showed identical diffusion times to those for TMR-labeled A38 alone, indicating a binding exclusively to VACV particles.