The
absence of detergent
and curvature makes nanodiscs excellent
membrane mimetics. The lack of structural and mechanistic model of
polymer-encapsulated lipid nanodiscs limits their use in the study
of the structure, dynamics, and functions of membrane proteins. In
this study, we parameterized and optimized the coarse-graining (CG)
bead mapping for two differently charged and functionalized copolymers,
containing styrene–maleic acid (SMAEA) and polymethacrylate
(PMAQA), for the Martini force-field framework and showed nanodisc
formation (<8 nm diameter) on a time scale of tens of microseconds
using molecular dynamics (MD) simulations. Structural models of ∼2.0
or 4.8 kDa PMAQA and ∼2.2 kDa SMAEA polymer-based lipid nanodiscs
highlight the importance of the polymer chemical structure, size,
and polymer–lipid ratio in the optimization of the nanodisc
structure. The ideal spatial arrangement of polymers in nanodiscs,
nanodisc size, and thermal stability obtained from our MD simulation
correlates well with the experimental observations. The polymer–nanodiscs
were tested for the reconstitution of single-pass or multipass transmembrane
proteins. We expect this study to be useful in the development of
novel polymer-based lipid nanodiscs and for the structural studies
of membrane proteins.