HCAtk and pyHCA: A Toolkit and Python API for the Hydrophobic Cluster Analysis of Protein Sequences

Tristan Bitard-Feildel; Isabelle Callebaut

The RNA binding activity is mediated by the region encompassing amino acids 45 to 181, such binding 188 activity is usually mediated by a high level of flexibility. The full-length protein is made of one or two Fig. S10 is another example of PDB protein sequence with low HCA score. The HCA plot represents 197 a sequence segment (from amino acids 500 to 629) of the the Staphylococcus aureaus surface protein G Figure S9 : PDB sequence with a low HCA score -example n o 1. The sequence region (Uniprot P5995), amino acids 49 to 174, PDB structure 2OFZ), corresponds to a RNA-binding domain, having large, flexible loops and a few regular secondary structures, constituting a β-sheet core. (α-helix: red rectangle β-strands: yellow arrows, annotation extracted from the experimental 3D structure 2OFZ).