The present invention is related to a structural protein of a parvovirus with an amino acid insertion at the insertion site I-453, a library comprising the protein, a multimeric structure comprising the protein, a nucleic acid encoding the protein, a vector, virus, or cell comprising the nucleic acid, a process for the preparation of the protein, a medicament comprising the protein, nucleic acid, or multimeric structure as well as methods and uses involving the protein, nucleic acid, or multimeric structure.