Analysis of the PlcA gene cluster revealed the presence of seven ORFs downstream of the PlcA-encoding gene (plcA), with sequence and organisational similarity to those found in the gene clusters responsible for GaaA and AciB production (Figure 2). Accordingly, plcA is followed by plcD, which encodes a putative 157 AA membrane associated protein with a DUF95 conserved domain. Recent research suggests that DUF95 proteins play a dual role in the biosynthesis of circular peptides, as an immunity-associated transporter protein and as a secretion-aiding agent (33). ORF plcI is immediately downstream of plcD, and encodes a 54 AA protein with a hypothetical function as an immunity protein. Kawai et al (34) showed that heterologous expression of GaaI in Lactococcus lactis confers a 7-fold higher resistance to gassericin A compared to a control strain.