Product Spotlight: Photoswitchable AzoPC

Posted on October 16, 2021

Photoswitchable Lipids

Azobenzenes are prototypical molecular “switches” that exist in two distinct states – cis and trans. These states have different physical properties. The trans isomer is energetically preferred in solution but adding a source of energy can cause the azobenzene moiety to “switch” from trans to cis and and be switched back to trans later. This results in an on-and-off molecular switch.

Lipids can be functionalized with azobenzene moieties to study light-induced alterations of phospholipid membranes. This is considered a noninvasive way to manipulate membrane proteins and cellular functions. Azobenzene moieties in lipids have been studied and used to alter membrane stiffness, fluidity, the formation of lipid domains, or to control membrane fission. This is important because the function of several membrane proteins is directly linked to the membrane environment and thus membrane lipids. Changes in lipid bilayers such as pressure variations are key factors in modulating the shape of the membrane and in turn, membrane protein functionality. Pressure-sensitive ion channels can be reversibly activated mechanically or chemically via changes in the membrane. Therefore, it is possible to control these processes with great resolution by using light-dependent photoswitches.

In the current study, researchers aimed to further understand the action of these photoswitchable lipids at the atomic level. To do so, they prepared liposomes made of POPE, POPG, and 18:0-azoPC. The light-induced alterations of the lipid bilayer within these mixed liposomes were probed and quantified using solid-state NMR. The dipolar order parameter changes of every single CH2 group were determined and the resulting measurements were supported by MAS-NOESY experiments to highlight AzoPC interactions.

This study successfully resolved how the trans-cis isomerization of AzoPC embedded lipid bilayers affects the membrane's bulk lipid properties. The isomerization triggers an overall reduction in the acyl chain order parameter. This effect was enhanced upon crowding of the membrane by reconstituting the membrane to include the membrane protein, DgkA. This revealed a site-specific increase in protein mobility. The data from this study illuminated at atomic resolution how photoswitches can alter lipid and protein dynamics. Furthermore, the study showed the application of photoswitchable liposomes as light-induced membrane protein modulators. This research was conducted via a collaboration between researchers from New York University and The Institute of Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance at Goethe University in Frankfurt, Germany.

We are excited to see our products being used in this cutting edge research, and we can’t wait to see what other fascinating research this collaboration yields.

If you are interested in research using Photoswitchable Lipids for your research, check out our library. We have added azobenzene moieties to several lipids to make it easy for you to study how light-induced isomerization can affect important biological lipid-related processes. And as always, when you choose Avanti, you choose the highest-quality lipid reagents for your projects.

Click below for more information on the research described above!

How Photoswitchable Lipids Affect the Order and Dynamics of Lipid Bilayers and Embedded Proteins

Image Credit: Original Research Publication