Beta-defensins bind microbial membranes causing disruption

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R-HSA-1467269
Type
Reaction [uncertain]
Species
Homo sapiens
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Binding and disruption of microbial membranes is widely believed to be the primary mechanism of action for beta-defensins. There is no direct evidence of this, but a growing number of studies support this model (Pazgier et al. 2006). Beta-defensins have antimicrobial properties that correlate with membrane permeabilization effects (Antcheva et al. 2004, Sahl et al. 2005, Yenugu et al. 2004). The sensitivity of microbes to beta-defensins correlates with the lipid composition of the membrane; more negatively-charged lipids correlate with larger beta-defensin 103-induced changes in membrane capacitance (Bohling et al. 2006). Beta-defensin-103 was observed to give rise to ionic currents in Xenopus membranes (Garcia et al. 2001) and cell wall perforation was observed in S. aureus when treated with HBD-3 (Harder et al. 2001). Two models explain how membrane disruption takes place. The 'pore model' postulates that beta-defenisns form transmembrane pores in a similar manner to alpha-defensins, while the 'carpet model' suggests that beta-defensins act as detergents, causing a less organised disruption. Beta-defensins have a structure that is topologically distinct from that of alpha-defensins, suggesting a different mode of dimerization and an electrostatic charge-based mechanism of membrane permeabilization rather than a mechanism based on formation of bilayer-spanning pores (Hoover et al. 2000).

Literature References
PubMed ID Title Journal Year
11085990 Isolation and characterization of human beta -defensin-3, a novel human inducible peptide antibiotic

Harder, J, Bartels, J, Christophers, E, Schroder, JM

J Biol Chem 2001
11702237 Identification of a novel, multifunctional beta-defensin (human beta-defensin 3) with specific antimicrobial activity. Its interaction with plasma membranes of Xenopus oocytes and the induction of macrophage chemoattraction

García, JR, Jaumann, F, Schulz, S, Krause, A, Rodríguez-Jiménez, J, Forssmann, U, Adermann, K, Klüver, E, Vogelmeier, C, Becker, D, Hedrich, R, Forssmann, WG, Bals, R

Cell Tissue Res 2001
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