Provided herein are de novo binding domain containing polypeptides (DBDpp) that specifically bind a target of interest. Nucleic acids encoding the DBDpp, and vectors and host cells containing the nucleic acids are also provided. Libraries of DBDpp, methods of producing and screening such libraries and the DBDpp identified from such libraries and screens are also encompassed. Methods of making and using the DBDpp are additionally provided. Such uses include, without limitation, affinity purification, and diagnostic and therapeutic applications.