pip install pdb-tools
# cif -> pdb pdb_fromcif AF-A0A009ET65-F1-model_v4.cif > AF-A0A009ET65-F1-model_v4.pdb
# pdb -> cif pdb_tocif AF-A0A009ET65-F1-model_v4.pdb > AF-A0A009ET65-F1-model_v4-x.cif
# Extracts residues 1 to 10 pdb_selres -1:10 AF-A0A009ET65-F1-model_v4.pdb