Interaction of the antimicrobial Peptide gomesin with model membranes : a calorimetric study

Domingues, Tatiana M. and Mattei, Bruno and Seelig, Joachim and Perez, Katia R. and Miranda, Antonio and Riske, Karin A.. (2013) Interaction of the antimicrobial Peptide gomesin with model membranes : a calorimetric study. Langmuir, 29 (27). pp. 8609-8618.

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Official URL: http://edoc.unibas.ch/dok/A6165337

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Gomesin is a potent cationic antimicrobial peptide (z = +6) isolated from the Brazilian spider Acanthoscurria gomesiana . The interaction of gomesin with large unilamellar vesicles composed of a 1:1 mixture of zwitterionic (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) and anionic (1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) phospholipids is studied with isothermal titration calorimetry (ITC). In parallel, light scattering and optical microscopy are used to assess peptide-induced vesicle aggregation. The ability of gomesin to permeabilize the membrane is examined with fluorescence spectroscopy of the leakage of 5,6-carboxyfluorescein (CF). Vesicles coated with 3 mol % 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (PE-PEG) lipids are also investigated to assess the influence of peptide-induced vesicle aggregation in the activity of gomesin. The ITC and light scattering titrations are done in two ways: lipid into peptide and peptide into lipid injections. Although some differences arise between the two setups, the basic interaction of gomesin with anionic vesicles is preserved. A surface partition model combined with the Gouy-Chapman theory is put forward to fit the ITC results. The intrinsic binding constant of gomesin is found to be K ≈ 10(3) M(-1). The interaction of gomesin with anionic membranes is highly exothermic and enthalpy-driven. Binding of gomesin is virtually always accompanied by vesicle aggregation and changes in membrane permeability, leading to CF leakage. Addition of PE-PEG to the membrane strongly attenuates vesicle aggregation but does not significantly change the mode of action of gomesin. The results point to a strong interaction of gomesin with the membrane surface, causing membrane rupture without a deep penetration into the bilayer core.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Former Organization Units Biozentrum > Biophysical Chemistry (Seelig J)
UniBasel Contributors:Seelig, Joachim
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Chemical Society
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:14 Nov 2017 12:56
Deposited On:13 Sep 2013 07:57

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