A protein is built from L-amino acids, so its crystal can hold no improper rotation of any kind — no mirror, no glide, no inversion centre.
Molecular point groups with their operations and character tables, the 230 space groups with a cell builder, and the 17 wallpaper and 7 frieze groups drawn live. The tool needs JavaScript, and WebGL2 for the 3D views; these are the pages it offers: