| Popis: |
We have recently demonstrated that the glycolipid trehalose dimycolate (TDM), a major outer membrane component of dehydration resistant Mycobacterium tuberculosis (MTb), can impart significant dehydration resistance to supported phospholipid membranes. We now report studies of other, related glycolipids both natural and synthetic that exhibit behavior similar to TDM, conferring protection from desiccation to membranes of which they are constituents. We examined solid-supported lipid monolayers, characterizing membrane integrity and two-dimensional fluidity before and after de- and re-hydration with fluorescence imaging and fluorescence recovery after photobleaching (FRAP). As with TDM, the degree of protection is dependent on the fraction of synthetic lipid in the monolayer and there is a distinct minimum fraction needed for protection by each glycolipid. We can control the synthetic lipid fluidity and minimum protecting fraction by designing and synthesizing lipids with particular hydrophobic chain lengths, saturation, and branching, thereby illuminating the role of molecular structure in biophysical function. The advent of these synthetic, protective glycolipids opens the door to the creation of lipid bilayers and liposomes since the relevant hydrophobic and hydrophilic domain sizes can be controlled. These new structures allow investigations of the physical origins of well-known mycobacaterial properties beyond dehydration resistance in controlled experimental contexts, such as the inhibition of membrane fusion. |
