Figure 2.

Structures of different bacterial autoinducers. (a) Examples of AHL autoinducers of some Gram-negative bacteria. (b) A selection of Gram-positive AIP autoinducers. The asterisk above the tryptophan (W) of ComX indicates a posttranslational isoprenylation of the peptide. The AIP molecules of Staphylococcus aureus are shown with the thioester bridge linking the indicated amino acid residues. The numbering I–IV refers to the S. aureus group classification. (c) AI-2 of Vibrio harveyi is a furanosyl borate diester, as determined by co-crystallization with the V. harveyi AI-2 receptor LuxP.