Preparation, Purification, and Use of Fatty Acid-containing Liposomes (News and Views)
Aaron E. Engelhart
Journal of Visualized Experiments, 2018.
Liposomes containing single-chain amphiphiles, particularly fatty acids, exhibit distinct properties compared to those containing diacylphospholipids due to the unique chemical properties of these amphiphiles. In particular, fatty acid liposomes enhance dynamic character, due to the relatively high solubility of single-chain amphiphiles. Similarly, liposomes containing free fatty acids are more sensitive to salt and divalent cations, due to the strong interactions between the carboxylic acid head groups and metal ions. Here we illustrate techniques for preparation, purification, and use of liposomes comprised in part or whole of single chain amphiphiles (e.g., oleic acids).
Four fluorogenic aptamers have reported NMR or crystal structures. (a) Spinach (PDB ID 4TS2) contains a G-quartet (red) immediately adjacent to its fluorogenic ligand, DFHBI (green), which makes interactions with a coplanar guanine residue (gray). This binding pocket is capped by a base triple (blue). (b) Mango (PDB ID 5V3F) also contains a G-quartet (red), immediately adjacent to its fluorogenic ligand, TO1–biotin (green). This binding pocket is capped by several unpaired nucleobases (blue). (c) The malachite green aptamer (PDB ID 1Q8N) contains a tetrad that is not a G-quartet (red) immediately adjacent to its fluorogenic ligand, malachite green (green). This binding pocket is capped by a G–C base pair (blue). The commonality of a binding site containing a quartet (but not necessarily a G-quartet) suggests that this may be a common structural motif for fluorogenic aptamers. (d) Corn (PDB ID 5BJO) is a dimer that contains tandem G-quartets (red) from two protomers and unpaired adenosines (blue), which comprise the binding site for its fluorogenic ligand, DFHO (green).