Development of a novel plasmid as a shuttle vector for heterologous gene expression in Mycoplasma yeatsii

► A novel plasmid, pMyBK1, has been identified in Mycoplasma yeatsii Type strain GIH. ► pMyBK1-based shuttle vectors transform M. yeatsii at high efficiency. ► Heterologous protein expression has been demonstrated for MALP-404. ► ORF2, dissimilar to known plasmid-encoded proteins, is essential for replication.