Comparison of the membrane interaction mechanism of two antimicrobial RNases: RNase 3/ECP and RNase 7

Marc Torrent, Daniel Sánchez, Víctor Buzón, M. Victòria Nogués, Josep Cladera, Ester Boix

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45 Citations (Scopus)

Abstract

Eosinophil cationic protein (ECP/RNase 3) and the skin derived ribonuclease 7 (RNase 7) are members of the RNase A superfamily. RNase 3 is mainly expressed in eosinophils whereas RNase 7 is primarily secreted by keratinocytes. Both proteins present a broad-spectrum antimicrobial activity and their bactericidal mechanism is dependent on their membrane destabilizing capacities. Using phospholipid vesicles as membrane models, we have characterized the protein membrane association process. Confocal microscopy experiments using giant unilamellar vesicles illustrate the morphological changes of the liposome population. By labelling both lipid bilayers and proteins we have monitored the kinetic of the process. The differential protein ability to release the liposome aqueous content was evaluated together with the micellation and aggregation processes. A distinct morphology of the protein/lipid aggregates was visualized by transmission electron microscopy and the proteins overall secondary structure in a lipid microenvironment was assessed by FTIR. Interestingly, for both RNases the membrane interaction events take place in a different behaviour and timing: RNase 3 triggers first the vesicle aggregation, while RNase 7 induces leakage well before the aggregation step. Their distinct mechanism of action at the membrane level may reflect different in vivo antipathogen functions. © 2009 Elsevier B.V. All rights reserved.
Original languageEnglish
Pages (from-to)1116-1125
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1788
DOIs
Publication statusPublished - 1 May 2009

Keywords

  • Antimicrobial protein
  • Confocal microscopy
  • Fluorescence spectroscopy
  • Liposome
  • Membrane
  • RNase

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