Fig. 2

Tolerance to substitutions in human influenza hemagglutinin as quantified by deep-sequencing and explained by PsychoProt analyses. Structure mapping of the amino acid descriptors that explain most of the variability observed in a deep-sequencing study of human influenza hemagglutinin (HA). The five most frequent descriptors, out of the eight physicochemical amino acid properties tested, are mapped on the structure of the protein trimer in the metastable prefusion conformation (PDB ID 1RVX). In each picture, residues colored in blue are those for which correlations against the descriptor were positive, while those in red correspond to negative correlations (only positive trends were observed for flexibility). In the picture for flexibility, we have also mapped the stalk helices (green), the A-helix (yellow), and the fusion peptide (magenta). These pictures were not rendered in the website but externally with the program PyMOL [66]