Fig 5.

Structural mapping of the 15-nt insertion sites. The insertions found in the input and passage 3 profiles were mapped onto the structures of NS7 (PDB accession number 3NAH) (A and B, respectively) and the P domain of VP1 (PDB accession number 3LQ6) (C and D, respectively). Blue residues highlight positions after which an insertion was detected. Where two insertions were made in a single codon with different outcomes, the most tolerated one was marked. In the P domain of VP1, the majority of insertions tolerated after three passages lie within flexible loop regions. The catalytic center in NS7 did not tolerate any insertions, further validating the profiling. The structures were mapped using Chimera software (UCSF).