scholarly journals Aqueous Liquid-Liquid Phase Separation of Natural and Synthetic Polyguanidiniums

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 649 ◽  
Author(s):  
Prather ◽  
Weerasekare ◽  
Sima ◽  
Quinn ◽  
Stewart
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Phase Separation ◽  
Solution Temperature ◽  
Titration Calorimetry ◽  
Polymer Backbone ◽  
Critical Solution Temperature ◽  
Upper Critical Solution Temperature ◽  
Positively Charged ◽  
Liquid Liquid Phase Separation

Protamines are natural polyguanidiniums, arginine(R)-rich proteins involved in the compaction of chromatin during vertebrate spermatogenesis. Salmine, a protamine isolated from salmon sperm, contains 65 mol% R residues, with positively charged guanidino (Gdm+) sidechains, and no other amino acids with ionizable or aromatic sidechains. Salmine sulfate solutions undergo liquid-liquid phase separation (LLPS) with a concentration-dependent upper critical solution temperature (UCST). The condensed liquid phase comprises 50 wt % water and >600 mg·ml−1 salmine with a constant 1:2 ratio of sulfate (SO42−) to Gdm+. Isothermal titration calorimetry, titrating Na2SO4 into salmine chloride above and below the UCST, allowed isolation of exothermic sulfate binding to salmine chloride from subsequent endothermic condensation and exothermic phase separation events. Synthetic random polyacrylate analogs of salmine, with 3-guanidinopropyl sidechains, displayed similar counterion dependent phase behavior, demonstrating that the LLPS of polyguanidiniums does not depend upon subunit sequence or polymer backbone chirality, and was due entirely to Gdm+ sidechain interactions. The results provide experimental evidence for like-charge pairing of Gdm+ sidechains, and an experimental approach for further characterizing these interactions.

scholarly journals Upper Critical Solution Temperature (UCST) Behavior of Coacervate of Cationic Protamine and Multivalent Anions

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 691 ◽  
Author(s):  
Hyungbin Kim ◽  
Byoung-jin Jeon ◽  
Sangsik Kim ◽  
YongSeok Jho ◽  
Dong Soo Hwang
Keyword(s):  
Electrostatic Interactions ◽  
Solution Temperature ◽  
Complex Coacervation ◽  
Critical Factors ◽  
Critical Solution Temperature ◽  
Temperature Changes ◽  
Upper Critical Solution Temperature ◽  
Large Asymmetry ◽  
Positively Charged ◽  
Liquid Liquid Phase Separation

Complex coacervation is an emerging liquid/liquid phase separation (LLPS) phenomenon that behaves as a membrane-less organelle in living cells. Yet while one of the critical factors for complex coacervation is temperature, little analysis and research has been devoted to the temperature effect on complex coacervation. Here, we performed a complex coacervation of cationic protamine and multivalent anions (citrate and tripolyphosphate (TPP)). Both mixtures (i.e., protamine/citrate and protamine/TPP) underwent coacervation in an aqueous solution, while a mixture of protamine and sodium chloride did not. Interestingly, the complex coacervation of protamine and multivalent anions showed upper critical solution temperature (UCST) behavior, and the coacervation of protamine and multivalent anions was reversible with solution temperature changes. The large asymmetry in molecular weight between positively charged protamine (~4 kDa) and the multivalent anions (<0.4 kDa) and strong electrostatic interactions between positively charged guanidine residues in protamine and multivalent anions were likely to contribute to UCST behavior in this coacervation system.

scholarly journals Pattern Regulation of DNA Hydrogels Formed by Lateral Phase Separation of DNA Nanostructures on Water-in-Oil Droplet Interfaces

2021 ◽  
Author(s):  
Yusuke Sato ◽  
Masahiro Takinoue
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Phase Separation ◽  
Solution Temperature ◽  
Dna Nanostructures ◽  
Artificial Cell ◽  
Lateral Phase Separation ◽  
Hydrogel Capsules ◽  
Liquid Liquid Phase Separation ◽  
Dna Hydrogels

<p>Phase separation is a key phenomenon in artificial cell construction. Recent studies have shown that the liquid-liquid phase separation of designed-DNA nanostructures induces the formation of liquid-like condensates that eventually become hydrogels by lowering the solution temperature. As a compartmental capsule is an essential artificial cell structure, many studies have focused on the lateral phase separation of artificial lipid vesicles. However, controlling phase separation using a molecular design approach remains challenging. Here, we present the lateral liquid-liquid phase separation of DNA nanostructures that leads to the formation of phase-separated capsule-like hydrogels. We designed three types of DNA nanostructures (two orthogonal and a linker nanostructure) that were adsorbed onto an interface of water-in-oil droplets via electrostatic interactions. The phase separation of DNA nanostructures led to the formation of hydrogels of bicontinuous, patch, and mix patterns, due to the immiscibility of liquid-like DNA during the self-assembly process. The frequency of appearance of these patterns was regulated by designing DNA sequences and altering the mixing ratio of the nanostructures. We constructed a phase diagram for the capsule-like DNA hydrogels by investigating pattern formation under various conditions. Our results provide a method for the design and control of phase-separated hydrogel capsules using sequence-designed DNAs. We envision that by incorporating various DNA nanodevices into DNA hydrogel capsules, the capsules will gain molecular sensing, chemical-information processing, and mechano-chemical actuating functions, allowing the construction of functional molecular systems.</p>

scholarly journals Pattern Regulation of DNA Hydrogels Formed by Lateral Phase Separation of DNA Nanostructures on Water-in-Oil Droplet Interfaces

2021 ◽  
Author(s):  
Yusuke Sato ◽  
Masahiro Takinoue
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Phase Separation ◽  
Solution Temperature ◽  
Dna Nanostructures ◽  
Artificial Cell ◽  
Lateral Phase Separation ◽  
Hydrogel Capsules ◽  
Liquid Liquid Phase Separation ◽  
Dna Hydrogels

<p>Phase separation is a key phenomenon in artificial cell construction. Recent studies have shown that the liquid-liquid phase separation of designed-DNA nanostructures induces the formation of liquid-like condensates that eventually become hydrogels by lowering the solution temperature. As a compartmental capsule is an essential artificial cell structure, many studies have focused on the lateral phase separation of artificial lipid vesicles. However, controlling phase separation using a molecular design approach remains challenging. Here, we present the lateral liquid-liquid phase separation of DNA nanostructures that leads to the formation of phase-separated capsule-like hydrogels. We designed three types of DNA nanostructures (two orthogonal and a linker nanostructure) that were adsorbed onto an interface of water-in-oil droplets via electrostatic interactions. The phase separation of DNA nanostructures led to the formation of hydrogels of bicontinuous, patch, and mix patterns, due to the immiscibility of liquid-like DNA during the self-assembly process. The frequency of appearance of these patterns was regulated by designing DNA sequences and altering the mixing ratio of the nanostructures. We constructed a phase diagram for the capsule-like DNA hydrogels by investigating pattern formation under various conditions. Our results provide a method for the design and control of phase-separated hydrogel capsules using sequence-designed DNAs. We envision that by incorporating various DNA nanodevices into DNA hydrogel capsules, the capsules will gain molecular sensing, chemical-information processing, and mechano-chemical actuating functions, allowing the construction of functional molecular systems.</p>

scholarly journals Liquid-Liquid Phase Separation of Tau Driven by Hydrophobic Interaction Facilitates Fibrillization of Tau

2021 ◽  
Vol 433 (2) ◽  
pp. 166731
Author(s):  
Yanxian Lin ◽  
Yann Fichou ◽  
Andrew P. Longhini ◽  
Luana C. Llanes ◽  
Pengyi Yin ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Hydrophobic Interaction ◽  
Liquid Phase Separation ◽  
Liquid Liquid Phase Separation

scholarly journals Amyloid Aggregation under the Lens of Liquid–Liquid Phase Separation

2020 ◽  
pp. 368-378
Author(s):  
Yanting Xing ◽  
Aparna Nandakumar ◽  
Aleksandr Kakinen ◽  
Yunxiang Sun ◽  
Thomas P. Davis ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Phase Separation ◽  
Amyloid Aggregation ◽  
Liquid Liquid Phase Separation

scholarly journals Observation of liquid-liquid phase separation of ataxin-3 and quantitative evaluation of its concentration in a single droplet using Raman microscopy

2021 ◽  
Author(s):  
Kazuki Murakami ◽  
Shinji Kajimoto ◽  
Daiki Shibata ◽  
Kunisato Kuroi ◽  
Fumihiko Fujii ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Neurodegenerative Diseases ◽  
Protein Aggregation ◽  
Quantitative Evaluation ◽  
Raman Microscopy ◽  
Liquid Phase Separation ◽  
Biological Processes ◽  
Single Droplet ◽  
Liquid Liquid Phase Separation

Liquid–liquid phase separation (LLPS) plays an important role in a variety of biological processes and is also associated with protein aggregation in neurodegenerative diseases. Quantification of LLPS is necessary to...

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