Figure 2. Workflows for membrane mimetic reconstitution of membrane proteins for bottom-up proteomics.

This schematic illustrates the membrane protein extraction methods using Nanodisc, Peptidisc and SMALPs. Membrane proteins are captured in nanodiscs with exogenous lipids after detergent removal using adsorbent beads. Proteins are surrounded by lipids and encircled by membrane scaffold proteins (MSPs). In the peptidisc method, membrane proteins are captured without exogenous lipids and detergent removal occurs using centrifugation filters. Membrane proteins are surrounded by multiple amphipathic peptides and affinity tags directly on the peptides enable the isolation of the membrane proteome. In SMALPs, membrane proteins are extracted directly from the membrane. The SMA polymer wraps around membrane proteins and excess polymer must be removed prior to LC–MS/MS.