The first of the cell–cell-signalling mechanisms is oligopeptide
signalling, which is the predominant signal used by Gram-positive
bacteria. Typically, a preprotein is generated, processed into the
active signalling peptide and exported from the cell. The biochemi-
cal cost of synthesis is relatively expensive, even for short peptides.
The chemical structure of the signal is precisely defined by the
sequence of amino acids [13]. The oligopeptide signals are highly
specific, sometimes allowing distinct signalling within different
strains of the same species