Roles of integral protein in membrane permeabilization by amphidinols |
| |
Authors: | Nagy Morsy Toshihiro Houdai Tohru Oishi Saburo Aimoto |
| |
Affiliation: | a Department of Chemistry, Graduate School of Science, Osaka University, 1-16 Machikaneyama, Toyonaka, Osaka 560-0043, Japan b Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan |
| |
Abstract: | Amphidinols (AMs) are a group of dinoflagellate metabolites with potent antifungal activity. As is the case with polyene macrolide antibiotics, the mode of action of AMs is accounted for by direct interaction with lipid bilayers, which leads to formation of pores or lesions in biomembranes. However, it was revealed that AMs induce hemolysis with significantly lower concentrations than those necessary to permeabilize artificial liposomes, suggesting that a certain factor(s) in erythrocyte membrane potentiates AM activity. Glycophorin A (GpA), a major erythrocyte protein, was chosen as a model protein to investigate interaction between peptides and AMs such as AM2, AM3 and AM6 by using SDS-PAGE, surface plasmon resonance, and fluorescent-dye leakages from GpA-reconstituted liposomes. The results unambiguously demonstrated that AMs have an affinity to the transmembrane domain of GpA, and their membrane-permeabilizing activity is significantly potentiated by GpA. Surface plasmon resonance experiments revealed that their interaction has a dissociation constant of the order of 10 μM, which is significantly larger than efficacious concentrations of hemolysis by AMs. These results imply that the potentiation action by GpA or membrane integral peptides may be due to a higher affinity of AMs to protein-containing membranes than that to pure lipid bilayers. |
| |
Keywords: | PC, phosphatidylcholine GpA, glycophorin A AM, amphidinol SDS, sodium dodecyl sulfate PAGE, polyacrylamide gel electrophoresis EDTA, ethylenediamine tetraacetic acid NHS, N-hydroxysuccinimide EDC, 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride CTAB, Cetyltrimethylammonium bromide SUV, small unilamellar vesicles LUV, large unilamellar vesicles MLV, multilamellar vesicles PBS, phosphate buffered saline BSA, bovine serum albumin GpA-TM, glycophorin A transmembrane peptide NIES, National Institute of Environmental Studies |
本文献已被 ScienceDirect 等数据库收录! |
|