Retracted Article: Polymer nanodiscs and macro-nanodiscs of a varying lipid composition

Abstract

Polymer lipid nanodiscs have enabled some exciting structural biology and nanobiotechnology applications. The use of a small molecular weight polymer (SMA-EA) has been demonstrated to dramatically increase the size of nanodiscs (upto ~60 nm diameter). Here, we report the first demonstration of the formation of macro-nanodiscs for a variety of lipids, and solid-state NMR experiments utilizing their magnetic-alignement properties.

Formation of pH‐Resistant Monodispersed Polymer–Lipid Nanodiscs

“…The magnitude of the observed quadrupolar coupling is dependent on the orientation of the quaternary ammonium C β −N bond vector with respect to the magnetic field direction (see the Supporting Information). The observed quadrupolar coupling magnitude of about 7.6 kHz arises from the choline group of DMPC and confirms the uniaxial orientation of nanodiscs with the lipid bilayer normal perpendicular to the magnetic field direction in agreement with 31 P NMR data, as reported for other polymer nanodiscs . The observed quadrupolar couplings of a magnitude of about 2.9 kHz and about 14 kHz are from the quaternary ammonium group of the SMA‐QA polymer.…”

An acid-compatible co-polymer for the solubilization of membranes and proteins into lipid bilayer-containing nanoparticles

“…In order to address the limited size range of nanodiscs formed by SMA, modification of a low-molecular weight SMA polymer by an amination reaction to form SMA-EA has been shown to form so-called ‘macro nanodiscs’. 48 , 49 SMA-EA stabilized nanodiscs have been shown to have diameters up to ∼60 nm whilst exhibiting alignment properties in external magnetic fields with demonstrated applications in 2D solid state NMR spectroscopy.…”

Formation of pH‐Resistant Monodispersed Polymer–Lipid Nanodiscs

“…30 nm) show three doublets corresponding to quadrupolar coupling values of about 14, 7.6, and 2.9 kHz (Figure 4b). [18] Theo bserved quadrupolar couplings of amagnitude of about 2.9 kHz and about 14 kHz are from the quaternary ammonium group of the SMA-QA polymer.T he presence of these two distinct doublets suggests that SMA-QA polymer belt completely surrounds the lipid bilayer in ah ighly ordered fashion and with orientations as shown in Figure 4e,w hich is similar to the orientations of detergent molecules in aligned bicelles. The observed quadrupolar coupling magnitude of about 7.6 kHz arises from the choline group of DMPC and confirms the uniaxial orientation of nanodiscs with the lipid bilayer normal perpendicular to the magnetic field direction in agreement with 31 PNMR data, as reported for other polymer nanodiscs.…”

“…The observed quadrupolar coupling magnitude of about 7.6 kHz arises from the choline group of DMPC and confirms the uniaxial orientation of nanodiscs with the lipid bilayer normal perpendicular to the magnetic field direction in agreement with 31 PNMR data, as reported for other polymer nanodiscs. [18] Theo bserved quadrupolar couplings of amagnitude of about 2.9 kHz and about 14 kHz are from the quaternary ammonium group of the SMA-QA polymer.T he presence of these two distinct doublets suggests that SMA-QA polymer belt completely surrounds the lipid bilayer in ah ighly ordered fashion and with orientations as shown in Figure 4e,w hich is similar to the orientations of detergent molecules in aligned bicelles. [19] Additional experiments using paramagnetic lanthanide ions to tilt the orientation of lipid macro-nanodiscs would reveal the exact orientations of the polymer molecules.A se xpected, the 14 NN MR spectrum of small nanodiscs (ca.…”