The present invention relates to nucleic acids encoding the novel parvoviral protein "assembly activating protein" (AAP), the encoded polypeptides, methods of producing the polypeptides, antibodies specific for AAP, the use of the nucleic acids for the preparation of the polypeptides, the use of the nucleic acids or the polypeptides for the preparation of the parvoviral particle and methods of producing parvoviral particles essentially consisting of VP3 by providing in addition to the coding sequence of the parvoviral structural protein VP3 a sequence fragment Z/a nucleic acid encoding AAP in the cell and expressing VP3 and fragment Z under control of a rep- independent promoter. Furthermore, the present invention relates to parvoviral particles essentially consisting of VP3 and/or obtainable by the above method as well as expression cassettes comprising (i) a heterologous promoter and (ii) VP3 coding sequence and/or fragment Z. The present invention further relates to a medicament, particularly a vaccine, comprising the parvoviral particles or expression cassettes and their use.La presente invención se refiere a un método para producir las partículas de parvovirus que consisten esencialmente de VP3, el método caracterizado porque comprende las etapas de: (i) proporcionar una célula capaz de expresar la VP3 a partir de una secuencia codificante de VP3 (cds) de un parvovirus, en donde la VP3 está bajo el control de un promotor independiente de Rep, y expresar un polipéptido adicional codificado por un ácido nucleico, en donde el polipéptido adicional comprende una secuencia de aminoácidos seleccionada del grupo que consiste de la SEC ID NO: 1, SEC ID NO: 2, SEC ID NO: 3, SEC ID NO: 4 SEC ID NO: 5 SEC ID NO: 6, SEC ID NO: 7, SEC ID NO: 8, SEC ID NO: 9, SEC ID NO: 10 SEC ID NO: 11, SEC ID NO: 12, SEC ID NO: 13, SEC ID NO: 14, SEC ID NO: 15, SEC ID NO:16, SEC ID NO: 17, SEC ID NO: 18, SEC ID NO: 19, SEC ID NO: 20, SEC ID NO: 21 Y LA SEC ID NO: 22, o una secuencia de ami
