This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
PDB pal EBI. All alpha proteins EF Handlike EFhand Parvalbumin Family Parvalbumin Protein Domain EBI pal November Parvalbumin Protein Domain Files uploaded by Nichalp's script
Page 2023 Free-images.com. All images are Public Domain