Dnia 2019-01-29 o godzinie 12:15 w sali 2011 Wydziału Fizyki UwB odbędzie się wykład, na którym prof. Horia I. Petrache (Department of Physics, Indiana University Purdue University Indianapolis, USA) wygłosi wykład pt:
„Electrostatic charging of lipid membranes by adenosine triphosphate”
Phospholipids (lipids in short) are found in biological membranes but are also of significant interest in material research due to their distinctive properties. In water or buffer solutions, the van der Waals attraction between lipid membranes causes them to form regular stacks of many layers with repeat lattice spacings (D-spacings) on the order of ten to a few hundred nanometers. D-spacing values depend not only on lipid type but also on the composition of water or buffer solution in which membranes are formed. Adenosine triphosphate (ATP), the molecule involved in the energy transfer in biological processes offers an interesting case study for tuning lipid membrane interactions. Using three complementary experimental methods: small-angle x-ray scattering (SAXS), NMR spectroscopy, and dynamic light scattering (DLS), we investigate lipid interactions in the presence of ATP and its hydrolysis products. We find that ATP binds to phospholipid surfaces as seen by standard NMR methods as well as by a net charging effect of membranes measured by SAXS and DLS. Interestingly, the membrane charging due to ATP gives rise to an unbinding transition of lipid multilayers which is not seen in the presence of monovalent salts. These findings can help quantitate energy transfers in biomembrane processes with possible applications to bioinspired materials.