Possible mechanism of structural transformations induced by StAsp-PSI in lipid membranes.
In the present work we have analyzed the effect of StAsp-PSI (plant-specific insert of potato aspartic protease) on the structural and thermotropic properties of the major phospholipid types of bacterial and animal cells. Results obtained suggest that StAsp-PSI induces a destabilization of the membrane bilayers, depending on the time of interaction between the protein and the bilayers, rather than on its concentration. This temporal delay would be consistent with a lateral diffusion of StAsp-PSI monomers to assemble into aggregates to form pores. Like with the results previously reported for the StAsp-PSI circular dichroism, data obtained here from IR spectroscopy show that there are slight changes in the StAsp-PSI secondary structure in the presence of lipid membranes; suggesting that these changes could be related with the StAsp-PSI self-association. Results obtained from steady-state fluorescence anisotropy and differential scanning calorimetry assays suggest that StAsp-PSI interacts with both uncharged and negatively charged phospholipids, modulates the phase polymorphic behavior of model membranes and partitions and buries differentially in the membrane depending on the presence of negatively charged phospholipids.
['Muñoz|Fernando|F|', 'Palomares-Jerez|M Francisca|MF|', 'Daleo|Gustavo|G|', 'Villalaín|José|J|', 'Guevara|M Gabriela|MG|']
D057055:Aspartic Acid Proteases D002152:Calorimetry, Differential Scanning D004134:Dimyristoylphosphatidylcholine D004926:Escherichia coli D008051:Lipid Bilayers D010539:Permeability D010715:Phosphatidylglycerols D010718:Phosphatidylserines D010940:Plant Proteins D017433:Protein Structure, Secondary D011994:Recombinant Proteins D011198:Solanum tuberosum D013055:Spectrophotometry, Infrared
Plant-specific insert Plant-specific insert IR differential scanning calorimetry 1,2-dimyristoylphosphatidylcholine 1,2-dimyristoylphosphatidylglycerol 1,2-dimyristoylphosphatidylserine 1,6-diphenyl-1,3,5-hexatriene 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene AMPs Antimicrobial protein Antitumor protein DMPC DMPG DMPS DPH DSC EPC EPG LUVs MLVs Membrane destabilization PSI Plant aspartic protease SAPLIPs TMA-DPH antimicrobial peptides and proteins egg l-α-phosphatidylcholine egg l-α-phosphatidylglycerol infrared spectroscopy large unilamellar vesicles multilamellar vesicles plant-specific insert saposin-like proteins α-Helix