Characterization of the replicon of a 51-kb native plasmid from the gram-positive bacterium Leifsonia xyli subsp. cynodontis.

The 4992-bp replicon of a large cryptic plasmid in the gram-positive bacterium Leifsonia xyli subsp. cynodontis was identified and sequenced. The replicon encoded two proteins essential for plasmid replication and stability. The putative replication protein (RepA) is homologous to that of the plasmids in mycobacterial pLR7 family, while the putative ParA protein immediately downstream of RepA is significantly homologous to the Walker-type ATPase required for partition of plasmid and chromosome of the gram-positive bacteria. These two proteins and other ORFs are clustered with the putative promoters and other regulatory sequences, illustrating an efficient organization of the replicon for this novel plasmid.