Bacterial lipoproteins: sorting mechanisms and biotechnological applications

The mechanism responsible for lipoprotein sorting is conserved among bacterial species. However, the final destination of lipoproteins may vary among species. In some species lipoproteins are surface-exposed while in others they are associated to the outer membrane but facing the periplasm. To elucidate whether the difference in lipoprotein location is intrinsic to lipotrotein sequence/structure or rather is due to specific transport systems present in some bacterial species and absent in others lipoproteins were expressed in different species and their compartmentalization analyzed. The data seem to indicate that the destiny of lipoproteins depends upon specific structural signatures but the recognition of such signatures can be species-specific. Interestingly, lipoproteins can be exploited as chaperones to deliver foreign proteins to the outer membrane compartment.