Abstract

Complex coacervation driven liquid-liquid phase separation (LLPS) of biopolymers has been attracting attention as a novel phase in living cells. Studies of LLPS in this context are typically of proteins harboring chemical and structural complexity, leaving unclear which properties are fundamental to complex coacervation versus protein-specific. This study focuses on the role of polyethylene glycol (PEG)—a widely used molecular crowder—in LLPS. Significantly, entropy-driven LLPS is recapitulated with charged polymers lacking hydrophobicity and sequence complexity, and its propensity dramatically enhanced by PEG. Experimental and field-theoretic simulation results are consistent with PEG driving LLPS by dehydration of polymers, and show that PEG exerts its effect without partitioning into the dense coacervate phase. It is then up to biology to impose additional variations of functional significance to the LLPS of biological systems.

Liquid-liquid phase separation occurs in cells and can be induced in artificial systems, but the mechanism of the effect of molecular crowders is unclear. Here dehydration entropy-driven phase separation of model charged polymers lacking any chemical complexity or hydrophobicity is shown to be enhanced by polyethylene glycol.

Details

Title
Dehydration entropy drives liquid-liquid phase separation by molecular crowding
Author
Park, Sohee 1   VIAFID ORCID Logo  ; Barnes, Ryan 2 ; Lin Yanxian 3 ; Byoung-jin, Jeon 4 ; Najafi Saeed 5 ; Delaney, Kris T 6 ; Fredrickson, Glenn H 7 ; Joan-Emma, Shea 8 ; Hwang, Dong Soo 9 ; Han Songi 10   VIAFID ORCID Logo 

1  Pohang University of Science and Technology (POSTECH), Division of Environmental Science and Engineering, Nam-gu, Republic of Korea (GRID:grid.49100.3c) (ISNI:0000 0001 0742 4007) 
2  University of California, Department of Chemistry and Biochemistry, Santa Barbara, USA (GRID:grid.133342.4) (ISNI:0000 0004 1936 9676) 
3  University of California, Department of Biomolecular Science and Engineering, Santa Barbara, USA (GRID:grid.133342.4) (ISNI:0000 0004 1936 9676) 
4  University of California, Materials Department, Santa Barbara, USA (GRID:grid.133342.4) (ISNI:0000 0004 1936 9676) 
5  University of California, Department of Chemistry and Biochemistry, Santa Barbara, USA (GRID:grid.133342.4) (ISNI:0000 0004 1936 9676); University of California, Materials Research Laboratory, Santa Barbara, USA (GRID:grid.133342.4) (ISNI:0000 0004 1936 9676) 
6  University of California, Materials Research Laboratory, Santa Barbara, USA (GRID:grid.133342.4) (ISNI:0000 0004 1936 9676) 
7  University of California, Materials Department, Santa Barbara, USA (GRID:grid.133342.4) (ISNI:0000 0004 1936 9676); University of California, Materials Research Laboratory, Santa Barbara, USA (GRID:grid.133342.4) (ISNI:0000 0004 1936 9676); University of California, Department of Chemical Engineering, Santa Barbara, USA (GRID:grid.133342.4) (ISNI:0000 0004 1936 9676) 
8  University of California, Department of Chemistry and Biochemistry, Santa Barbara, USA (GRID:grid.133342.4) (ISNI:0000 0004 1936 9676); University of California, Department of Physics, Santa Barbara, USA (GRID:grid.133342.4) (ISNI:0000 0004 1936 9676) 
9  Pohang University of Science and Technology (POSTECH), Division of Environmental Science and Engineering, Nam-gu, Republic of Korea (GRID:grid.49100.3c) (ISNI:0000 0001 0742 4007); Pohang University of Science and Technology (POSTECH), Division of Integrative Biosciences and Biotechnology, Nam-gu, Republic of Korea (GRID:grid.49100.3c) (ISNI:0000 0001 0742 4007) 
10  University of California, Department of Chemistry and Biochemistry, Santa Barbara, USA (GRID:grid.133342.4) (ISNI:0000 0004 1936 9676); University of California, Department of Chemical Engineering, Santa Barbara, USA (GRID:grid.133342.4) (ISNI:0000 0004 1936 9676) 
Publication year
2020
Publication date
2020
Publisher
Nature Publishing Group
e-ISSN
23993669
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1038/s42004-020-0328-8
ProQuest document ID
2417700355
Copyright
© The Author(s) 2020. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.