FIG. 3.

Examples of mutants with distinct binding properties. Shown are examples of the four categories of mutants described in the text. Mutant L166E has reduced middle T binding compared to the wild type (WT) but full-strength B subunit binding; mutant W257A binds T antigens but little of the B subunits. AΔ5 is a negative control that does not bind any B subunit or T antigen (8, 15). An additional control for T-antigen binding, in which T antigens were not added before immunoprecipitation, is shown at the bottom. SV, SV40; Py, polyomavirus; ST, small t; MT, middle T.