X-ray scattering studies of model lipid membrane interacting with purothionin provide support for a previously proposed mechanism of membrane lysis |
| |
Authors: | Jaroslaw Majewski Boguslaw Stec |
| |
Affiliation: | (1) Manuel Lujan Jr. Neutron Scattering Center, Los Alamos National Laboratory, MS-H805, Los Alamos, NM 87545, USA;(2) Infectious and Inflammatory Disease Center, Burnham Institute for Medical Research, 10901 N. Torrey Pines Rd., La Jolla, CA 92037, USA; |
| |
Abstract: | Thionins, ubiquitous plant toxins, are believed to act by lysing the membrane of pathogenic organisms. Several competing mechanisms were proposed for the lysis of phospholipid membranes by the toxins. In order to study in more detail the proposed mechanisms and possibly resolve among the competing proposals, the interactions of purothionins with a model lipid membrane in the form of a monolayer were studied. The monolayer formed at the air-water interface was studied by synchrotron X-ray reflectivity and grazing incidents diffraction methods. The model membrane was composed of 90:10 mol% DPPC:DPPS (dipylmitoyl phosphatidylcholine:dipylmitoyl phosphatidylserine). The protein interaction with the monolayer disturbs the in-plane and out-of-plane order of phospholipids, increases the amount of the liquid phase of the monolayer, and increases the average surface area per alkyl chain. The results indicate that the protein is bound only transiently, and after ~4 h most of the properties of the monolayer are reminiscent of the pure DPPC monolayer suggesting partial withdrawal of DPPS. Obtained electron density distributions perpendicular to the membrane interface do not show any significant contribution from the adsorbed proteins, further supporting the withdrawal hypothesis. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|