Correction for '3D printing of reactive macroporous polymers
thiol-ene chemistry and polymerization-induced phase separation' by Nikolaj K. Mandsberg
,
, 2024, https://doi.org/10.1039/d4cc00466c.
Proteins that undergo liquid–liquid phase separation (LLPS) have been shown to play a critical role in many physiological functions through formation of condensed liquid-like assemblies that function ...as membraneless organelles within biological systems. To understand how different proteins may contribute differently to these assemblies and their functions, it is important to understand the molecular driving forces of phase separation and characterize their phase boundaries and material properties. Experimental studies have shown that intrinsically disordered regions of these proteins are a major driving force, as many of them undergo LLPS in isolation. Previous work on polymer solution phase behavior suggests a potential correspondence between intramolecular and intermolecular interactions that can be leveraged to discover relationships between single-molecule properties and phase boundaries. Here, we take advantage of a recently developed coarse-grained framework to calculate the θ temperature Tθ
, the Boyle temperature TB
, and the critical temperature Tc
for 20 diverse protein sequences, and we show that these three properties are highly correlated. We also highlight that these correlations are not specific to our model or simulation methodology by comparing between different pairwise potentials and with data from other work. We, therefore, suggest that smaller simulations or experiments to determine Tθ
or TB
can provide useful insights into the corresponding phase behavior.
The thermally induced phase separation (TIPS) method is regaining momentum as a competitive platform to fabricate highly porous microporous membranes. In membrane technology, there has been an active ...search for more sustainable ways to fabricate polymeric membranes using green solvents. Rhodiasolv PolarClean® is a recently identified environmentally friendly TIPS solvent that shows high potential for the preparation of microporous PVDF membranes. Interestingly, its high miscibility with water induces a nonsolvent-induced phase separation (NIPS) effect on the membrane surface and this simultaneous NIPS-TIPS effect is referred to as the combined NIPS-TIPS (N-TIPS) method. In this work, a thorough investigation was carried out to understand the underlying phenomena in the membrane formation kinetics during the N-TIPS process. It was found that the NIPS and TIPS morphology can be tailored to control the mechanical properties, pore size distribution, and flux of the prepared membranes. For instance, increasing the coagulation bath solvent concentration facilitated the formation of a spherulitic morphology, whereas increasing the bath temperature induced the formation of a bicontinuous morphology free of macrovoids. It was determined that by controlling the phase separation kinetics, the mechanical properties of the prepared PVDF membranes could be remarkably improved from 0.9MPa to 6.1MPa. Several pore-forming additives including polyvinylpyrrolidone, Pluronics F-127, LiCl, and glycerol were employed to induce surface pores and their effects were thoroughly characterized. The membranes prepared with Pluronic additives exhibited high water permeabilities up to 2800Lm−2h−1bar−1 with narrow pore size distributions.
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•Microporous PVDF membranes were prepared via TIPS using an environmental friendly solvent.•The NIPS effect on membrane surface during TIPS process was investigated in detail.•Pluronic F127 additive was found to be an effective pore forming agent.
Tightly packed complexes of nucleocapsid protein and genomic RNA form the core of viruses and assemble within viral factories, dynamic compartments formed within the host cells associated with human ...stress granules. Here, we test the possibility that the multivalent RNA‐binding nucleocapsid protein (N) from severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) condenses with RNA via liquid–liquid phase separation (LLPS) and that N protein can be recruited in phase‐separated forms of human RNA‐binding proteins associated with SG formation. Robust LLPS with RNA requires two intrinsically disordered regions (IDRs), the N‐terminal IDR and central‐linker IDR, as well as the folded C‐terminal oligomerization domain, while the folded N‐terminal domain and the C‐terminal IDR are not required. N protein phase separation is induced by addition of non‐specific RNA. In addition, N partitions in vitro into phase‐separated forms of full‐length human hnRNPs (TDP‐43, FUS, hnRNPA2) and their low‐complexity domains (LCs). These results provide a potential mechanism for the role of N in SARS‐CoV‐2 viral genome packing and in host‐protein co‐opting necessary for viral replication and infectivity.
SYNOPSIS
Viruses can assemble nucleocapsid protein (N) and genomic RNA in dynamic compartments containing host ribonucleoproteins. We show SARS‐CoV‐2 N undergoes liquid‐liquid phase separation (LLPS) with RNA and enters droplets formed by human hnRNPs.
N phase separation in vitro in physiological buffer conditions is enhanced by RNA.
N‐terminal and linker disordered domains and C‐terminal folded dimerization domain are essential for robust LLPS.
RNA sequence specificity is not necessary for enhancing N LLPS.
N partitions into phase separated forms of hnRNPA2, TDP‐43, and FUS.
The nucleocapsid protein from SARS‐CoV‐2 undergoes liquid‐liquid phase separation with RNA and can partition into droplets formed by TDP‐43, FUS or hnRNPA2.
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