Nanodisc technology is an approach to render membrane proteins soluble in aqueous solutions in a native-like bilayer environment, where the membrane proteins remain stable and active. The Nanodisc concept is derived from high density lipoprotein (HDL) particles and their primary protein component, apolipoprotein. The Nanodisc is a non-covalent structure of phospholipid bilayer and membrane scaffold protein (MSP), a genetically engineered protein, which mimics the function of Apolipoprotein A-1 (ApoA-1).
The first MSP, MSP1, was engineered with its sequence based on the sequence of A-1, but without the globular N-terminal domain of native A-1. The MSP1E3D1 D73C variant of MSP1 differs from MSP1 in the following facets:
It deletes the first 11 amino acids in the Helix 1 portion (referred to as “H0.5” in the accompanying figure) of the original MSP1 sequence3 (which is known separately as MSP1D1).
It repeats the Helix 4 (H4), Helix 5 (H5) and Helix 6 (H6) sequences of the original MSP1 sequence between the parent Helix 6 (H6) and Helix 7 (H7) segments of MSP1D1.
It substitutes a cysteine (C) residue for an aspartic acid (D) residue in the Helix 2 (H2) portion of the protein, at position 73 of the original native A-1 sequence.
The initial histidine-tag is one amino acid shorter.
