In vitro studies on the stability and reconstitution of aquaporin PM28A

Abstract

Aquaporins are small integral membrane proteins composed of six transmembrane α-helices with a common topology, that transport either water alone or water and small solutes across the lipid membrane. The spinach protein PM28A is a major aquaporin in the leaf plasma membrane, comprising around 10% of the total membrane protein. The study of membrane proteins in vitro remains challenging, partly due to problems encountered when working outside the native lipid environment. Maintaining protein stability and function can be difficult, therefore establishing optimal conditions is essential. PM28A has been unfolded in the presence of different denaturing agents and subsequently refolded into detergent micelles, and reconstituted into artificial lipid systems. Folding and activity were found to be influenced by the choice of liposome composition.