Impact of macromolecular crowding on RNA/spermine complex coacervation and oligonucleotide compartmentalization

A. M. Marianelli, B. M. Miller, C. D. Keating

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

We report the effect of neutral macromolecular crowders poly(ethylene glycol) (PEG) (8 kDa) and Ficoll (70 kDa) on liquid-liquid phase separation in a polyuridylic acid (polyU)/spermine complex coacervate system. The addition of PEG decreased both the amount of spermine required for phase separation and the coacervation temperature (TC). We interpret these effects on phase behavior as arising due to excluded volume and preferential interactions on both the secondary structure/condensation of spermine-associated polyU molecules and on the association of soluble polyU/spermine polyelectrolyte complexes to form coacervate droplets. Examination of coacervates formed in the presence of fluorescently-labeled PEG or Ficoll crowders indicated that Ficoll is accumulated while PEG is excluded from the coacervate phase, which provides further insight into the differences in phase behavior. Crowding agents impact distribution of a biomolecular solute: partitioning of a fluorescently-labeled U15 RNA oligomer into the polyU/spermine coacervates was increased approximately two-fold by 20 wt% Ficoll 70 kDa and by more than two orders of magnitude by 20 wt% PEG 8 kDa. The volume of the coacervate phase decreased in the presence of crowder relative to a dilute buffer solution. These findings indicate that potential impacts of macromolecular crowding on phase behavior and solute partitioning should be considered in model systems for intracellular membraneless organelles.

Original languageEnglish (US)
Pages (from-to)368-378
Number of pages11
JournalSoft matter
Volume14
Issue number3
DOIs
StatePublished - Jan 1 2018

Fingerprint

crowding
Spermine
oligonucleotides
Oligonucleotides
Polyethylene glycols
Poly U
Ficoll
RNA
acids
Phase behavior
solutes
Phase separation
organelles
complex systems
oligomers
glycols
liquid phases
ethylene
condensation
buffers

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Condensed Matter Physics

Cite this

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title = "Impact of macromolecular crowding on RNA/spermine complex coacervation and oligonucleotide compartmentalization",
abstract = "We report the effect of neutral macromolecular crowders poly(ethylene glycol) (PEG) (8 kDa) and Ficoll (70 kDa) on liquid-liquid phase separation in a polyuridylic acid (polyU)/spermine complex coacervate system. The addition of PEG decreased both the amount of spermine required for phase separation and the coacervation temperature (TC). We interpret these effects on phase behavior as arising due to excluded volume and preferential interactions on both the secondary structure/condensation of spermine-associated polyU molecules and on the association of soluble polyU/spermine polyelectrolyte complexes to form coacervate droplets. Examination of coacervates formed in the presence of fluorescently-labeled PEG or Ficoll crowders indicated that Ficoll is accumulated while PEG is excluded from the coacervate phase, which provides further insight into the differences in phase behavior. Crowding agents impact distribution of a biomolecular solute: partitioning of a fluorescently-labeled U15 RNA oligomer into the polyU/spermine coacervates was increased approximately two-fold by 20 wt{\%} Ficoll 70 kDa and by more than two orders of magnitude by 20 wt{\%} PEG 8 kDa. The volume of the coacervate phase decreased in the presence of crowder relative to a dilute buffer solution. These findings indicate that potential impacts of macromolecular crowding on phase behavior and solute partitioning should be considered in model systems for intracellular membraneless organelles.",
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Impact of macromolecular crowding on RNA/spermine complex coacervation and oligonucleotide compartmentalization. / Marianelli, A. M.; Miller, B. M.; Keating, C. D.

In: Soft matter, Vol. 14, No. 3, 01.01.2018, p. 368-378.

Research output: Contribution to journalArticle

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