Membrane mimetics for solution NMR studies of membrane proteins

Membrane proteins are one of the most challenging and attractive objects in modern structural biology, as they are targets for the majority of medicines. However, studies of membrane proteins are hindered by several obstacles, including their low ability to crystallize, highly dynamic behavior of some of their domains, and need for membrane-like environment. Although solution nuclear magnetic resonance (NMR) is a very powerful technique of structural biology in terms of the amount of provided data, it imposes several limitations on the object under investigation, with the main constraint being related to the size of the object. For this reason, the membrane mimetic has to form particles of small size and simultaneously to properly simulate the bilayer membrane to be applicable for solution NMR spectroscopy. Here we review the recent advances in the field of membrane mimetics for solution NMR studies, discuss the advantages and drawbacks of specific membrane-like environments, and formulate the criteria for the selection of proper environment for a particular membrane protein or domain.