Determination of liposome size: a tool for protein reconstitution

Reconstitution of proteins into liposomes is a widespread approach to analyzing their biological function. Many protocols exist for this procedure and for the subsequent analysis of proteins. Here, we establish a procedure for preparation and analysis of liposomes with a lipid composition reflecting the outer envelope of chloroplasts. First, the stability of the liposomes in different buffer systems was investigated to provide information for the storage of the reconstituted system. Then, the size of the liposomes created by filtration through a polycarbonate filter dependent on the lipid composition was analyzed. Subsequently, solubilization of the liposomes composed of lipids with the outer envelope composition by dodecylmaltoside and octylglucoside as a preceding step of reconstitution was studied. Finally, we developed a straightforward method to determine the size of liposomes by absorption spectroscopy. The described setup allows the construction of reconstitution protocols, including the final determination of the liposome size.