Decoding distinct membrane interactions of HIV-1 fusion inhibitors using a combined atomic force and fluorescence microscopy approach

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• 作者：Henri G. Franquelim ; Diana Gaspar ; A. Salomé ; Veiga ; Nuno C. Santos ; Miguel A.R.B. Castanho ; ^{macastanho@fm.ul.pt}
• 关键词：Fusion inhibitors ; Enfuvirtide ; T-1249 ; Supported lipid bilayers ; Atomic force microscopy ; Fluorescence microscopy
• 刊名：Biochimica et Biophysica Acta (BBA)/Biomembranes
• 出版年：2013
• 出版时间：August, 2013
• 年：2013
• 卷：1828
• 期：8
• 页码：1777-1785
• 全文大小：2493 K

文摘

Enfuvirtide and T-1249 are two potent HIV-1 fusion inhibitor peptides. Recent studies indicate that lipids play an important role in the mode of action of those bioactive molecules. Using a combined tandem atomic force microscopy (AFM)-epifluorescence microscopy approach, we studied the interaction of both enfuvirtide and T-1249 with supported lipid bilayers. Fluid (l_d)-gel (s_o) and l_d-liquid ordered (l_o) phase-separated membrane systems were tested. Results, especially for T-1249, show significant lipid membrane activity at a 15 ¦ÌM peptide concentration. T-1249, in opposition to enfuvirtide, induces an increase in membrane surface roughness, decrease in membrane fluidity, bilayer thinning at l_d domains and disruption of the s_o domain borders. In terms of structural properties, both enfuvirtide and T-1249 possess distinct functional hydrophobic and amphipathic domains of HIV gp41. While enfuvirtide only yields the tryptophan-rich domain (TRD), T-1249 possesses both TRD and pocket-binding domain (PBD). TRD increases the hydrophobicity of the peptide while PBD enhances the amphipathic characteristics. As such, the enhanced membrane activity of T-1249 may be explained by a synergism between its amphipathic N-terminal segment and its hydrophophic C-terminal. Our findings provide valuable insights on the molecular-level mode of action of HIV-1 fusion inhibitors, unraveling the correlation between their structural properties and membrane interactions as a factor influencing their antiviral activity. Ultimately, this work validates the applicability of a combined AFM and fluorescence approach to evaluate the mechanic and structural properties of supported lipid bilayers upon interaction with membrane-active peptides.