Micro-Raman spectroscopic analysis of liquid–liquid phase separation

Abstract

Liquid−liquid phase separation (LLPS) plays a significant role in various biological processes, including the formation of membraneless organelles and pathological protein aggregation. Although many studies have found various factors that...

Ultrafast Spectroscopy Reveals Slow Water Dynamics in Biocondensates

“…This shift is likely due to the strong arginine–phosphate electrostatic interactions, cation–pi interactions, pi–pi stacking, or a combination of these interactions. ,, However, the small changes in the spectra indicate that the environment remains largely unchanged within the condensate phase. This is consistent with previous studies suggesting that biomolecules remain hydrated within the condensate phase. − Simulations present a similar picture, and the H-bond populations computed in the condensate, dilute, and single-peptide phases show no qualitative changes in the populations of the amide or arginine groups, consistent with the experiment (Figure S8). This suggests that the strong arginine–phosphate H-bond interactions do not perturb the local environment and that water molecules can provide a substantially similar H-bonding environment.…”

“…We attribute these effects to the bound water within the condensate phase. Although the slowdown observed in the amide is consistent with similarly crowded environments, the effects on arginine are considerably more significant. ,, This suggests that strong electrostatic interactions around these groups yield considerably slower dynamics for water molecules within the first solvation shell of the peptide or nucleic acids . Based on this evidence, we hypothesize that despite the strong electrostatic and cation–pi interactions and not overall crowding, they are the drivers of this slowdown.…”

OpiCa1-PEG-PLGA nanomicelles antagonize acute heart failure induced by the cocktail of epinephrine and caffeine

“…The OpiCa1-PEG-PLGA polymers were firstly synthesized through an amide crosslink between the amino group of OpiCa1 and the carboxyl group of PEG-PLGA in the presence of the two activators EDC and NHS which was to dissolve in different organic solvents, including DMSO, MeOH, DCM and IPA, to form fat-soluble films, and then use surfactant deionized water to disperse them into the water phase to spontaneously form nanomicelles which were composed of OpiCa1 polypeptide molecules as the shell, and the PLGA end of PEG-PLGA as the core to form an elliptical spherical structure [ [38] , [39] , [40] ]. ( Fig.…”

In situ Quantification of Biomolecular Concentration of Cytoplasmic Membraneless Organelles in a Living Cell

“…14,15 This technique allows the concentration determination of biomolecules in a single droplet in buffer solutions and can also be applied to quantify local crowding environments in a living cell. 16,17 The application of Raman measurements to droplets in buffer solutions has been reported in recent years; 14,15,[18][19][20][21] however, its application to actual intracellular droplets is very limited. The drawback of Raman measurement is the low scattering cross section resulting in the low signal level.…”