The levels of protein A and immunoglobulin G (IgG) from beads showed no significant difference across all AP samples including the mock negative controls (Figure S1A,B, p > 0.2, Tukey-HSD, and Conover post-hoc test), which indicates that the variation of CP levels across the different infection conditions was not due to technical inconsistency in the amount of beads and/or antibody but rather, due to differences in protein translation efficiency, virus replication or stability in these mutants. Here, CP is linked to infection.