Bacteriocin receptors

His major scientific interests are bacterial virulence and various aspects of bacteriocins and toxins including quorum sensing regulation, mode of action, and mechanisms involved in immunity and receptor targeting. 

FIGURE 1.1 Probiotics may protect against infection by pathogens through (1) Direct antagonism via bacteriocin production. (2) Immunomodulation via immune cell (T-cell, Dendritic cell) activation. (3) Improvement of epithelial barrier function and competitive exclusion via induction of mucus and blocking of epithelial binding receptors. 

Pediocin PA-1 was shown to dissipate the proton motive force and inhibit the amino acid transport in sensitive cells [75]. lipoteichoic acid is essential for non-specific pediocin AcH binding, and sensitive cells present a specific receptor that potentiates contact with the membrane [17,66]. Pediocin PA-1 displays an important M-terminal -Y-G-N-G-V-X-C- consensus common with other anti-Listeria bacteriocins such as sakacin A (= curvacin A) and P, and leucocin A. This finding suggests an important role of the N-terminus in either the recognition and/or activity of the pediocin-like bacteriocins. 

The need of a receptor, present in the target membranes of bacteriocin susceptible organisms has been extensively studied for microcin 25, produced... 

In conclusion, pore formation in the cytoplasmic membrane seems to be a common mode of action of those LAB bacteriocins for which the mode of action has been determined. Some of the class II bacteriocins (lactococcin A, B, G and lactacin F) require a specific receptor molecule for adsorption, whereas nisin also acts on Hposomes and exerts a receptor-independent action. Differences between narrow or wide host-range bacteriocins seem to be correlated with this aspect of a specific receptor, needed for activity. However, which bacteriocin domains confer binding specificities to lipid, protein, or reactive groups remain to be elucidated. 

It should also be mentioned that some Class II bacteriocins, namely lactococcin 972 (Class Ed) and garvicin A, can act by inhibiting septum formation (Martinez et al. 2000, 2008 Maldonado-Barragan et al. 2013), but whether or not these activities are receptor-mediated has not been conclusively confirmed. But it is interesting to note that the activity of lactococcin 972 is lipid Il-dependent, since such lipid II dependence is usually associated with lantibiotics. 

Ovchinnikov, K.V., Kristiansen, R.E., Uzelac, G., et al. (2014). Defining the structure and receptor binding domain of the leaderless bacteriocin LsbB. 75ioZ Chem 289, 23838-23845. 

Yoneyama, F., Imura, Y., Ichimasa, S., et al. (2009). Lacticin Q, a lactococcal bacteriocin, causes high-level membrane permeability in the absence of specific receptors. Appl Environ Microbiol 75, 538-541. 

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