Fig 3. Round 1 design of viscosity reducing mutations.

Mutations in round 1 were designed to reduce the overall negative charge and to reduce the negative charge patches. These patches were identified by generating an electrostatic potential energy surface using Delphi [30–32] seen in (a). Here red is negative charge potential and blue is positive charge potential. Mutations were also generated to avoid the interface residues (green) that are identified from the PDB structure 4qci and seen in (b). The mutants that were selected are shown in (c) where removal of negative charge sites is in red, addition of positive charge sites is in blue and the mutants for changing the FW1 to remove the clipped species are shown in light blue. All sites are annotated with Kabat positions.