Macromolecular Crowding-Induced Unusual Liquid-Liquid Phase Separation of Human Serum Albumin via Soft Protein-Protein Interactions.
Chinmaya Kumar PatelShivendra SinghBhawna SainiTushar Kanti MukherjeePublished in: The journal of physical chemistry letters (2022)
Macromolecular crowding has a profound impact on the conformational dynamics and intermolecular interactions of biological macromolecules. In this context, the role of inert synthetic crowders in the protein-protein interactions of globular proteins is poorly understood. Here, using native human serum albumin (HSA) under physiological conditions, we show that macromolecular crowding induces liquid-liquid phase separation (LLPS) via liquid-like membrane-less droplet formation in a concentration- and time-dependent manner. Circular dichroism measurements reveal significant alteration in the secondary structure of HSA inside the droplet during aging. In contrast, at a high protein concentration, a liquid-to-solid-like phase transition has been observed upon maturation. Our findings reveal that the LLPS of HSA is mainly driven by enthalpically controlled intermolecular protein-protein interactions via hydrophobic contacts involving aromatic and/or nonaromatic residues. Moreover, modulation of LLPS of HSA has been demonstrated upon denaturation and ligand binding. This study highlights the importance of soft protein-protein interactions of globular proteins in a crowded cellular environment in driving the LLPS.
Keyphrases
- human serum albumin
- single cell
- ionic liquid
- high throughput
- genome wide
- magnetic resonance
- high glucose
- molecular dynamics
- magnetic resonance imaging
- energy transfer
- diabetic rats
- molecular dynamics simulations
- single molecule
- intellectual disability
- gene expression
- protein protein
- endothelial cells
- computed tomography
- dna methylation
- contrast enhanced
- small molecule
- binding protein
- aqueous solution
- stress induced