کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1944461 | 1053211 | 2012 | 8 صفحه PDF | دانلود رایگان |
The membrane interaction of the cyclotide kalata B1, an all-d-analogue and a single alanine substituted analogue (G6A), was studied by surface plasmon resonance (SPR) and atomic force microscopy (AFM). Kalata B1 showed a strong binding selectivity for dimyristoyl-phosphatidylethanolamine (DMPE) compared to dimyristoyl-phoshatidylcholine (DMPC)-containing lipids. However, when the interaction was visualized by AFM the peptide interacted with DMPC and DMPE in a similar manner. There was no apparent change in membrane morphology with either lipid, suggesting that kalata B1 does not act via a carpet-like disruption mechanism. The d-analogue showed similar binding by SPR and the same strong selectivity for DMPE, indicating that the membrane-interaction and lipid selectivity are not stereo-specific. SPR studies of the G6A analogue revealed that it interacted in a similar way to kalata B1 on the DMPC containing lipids, but showed no increased response on the DMPE containing lipids observed for kalata B1 and d-kalata B1. These results indicate that the Gly6 residue directly influences membrane binding as it is located near a putative membrane interacting hydrophobic patch. Overall, the data suggest that very small changes in amino acid composition (with no change in conformation) can influence specific self-association in combination with membrane binding and mediate the activity of kalata B1.
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► The membrane binding of kalata B1 was studied by surface plasmon resonance.
► Kalata B1 and a D-analogue selectively bound to phosphatidylethanolamine.
► The membrane binding and lipid selectivity are not stereo-specific.
► A single alanine mutant (G6A) showed no increased response on DMPE.
► Small changes in sequence affect membrane binding and the activity of kalata B1.
Journal: Biochimica et Biophysica Acta (BBA) - Biomembranes - Volume 1818, Issue 9, September 2012, Pages 2354–2361