Intrinsically disordered proteins (IDPs) represent a unique and functionally significant class of biomolecules that play key regulatory roles in higher organisms. Unlike structured proteins, IDPs lack a fixed three-dimensional conformation, a feature that enables their dynamic interactions and allows their biochemical activity to be finely tuned by temperature and the cellular environment. From a biophysical perspective, IDPs behave as heteropolymers with extensive conformational flexibility, governed by non-covalent interactions among their amino acid side chains under specific physicochemical conditions.

In this seminar, I will discuss the fundamental physicochemical properties of proteins as heteropolymers, focusing on how hydrodynamic parameters relate to structural characteristics. I will highlight common challenges in interpreting the molecular properties of IDPs, in contrast to folded proteins. The talk will include recent findings from our research on interactions and liquid–liquid phase separation in two systems: cytoplasmic proteins involved in human gene expression and extracellular coral acid-rich proteins implicated in biomineralization, based on fluorescence correlation spectroscopy and confocal imaging.