Intrinsically disordered proteins (IDP) serve as one of the key components in the proteome. In contrast to the dominant class of cytosolic globular proteins, they harbor an enormous amount of physical flexibility or structural plasticity enforcing them to be retained in conformational ensembles rather than well defined stable folds. Previous studies have revealed the importance of transient dynamical phenomena like that of salt-bridges within them to support their physical flexibility and have

more »

... urther suggested their functional importance. For their characteristic flexibility, these proteins remain amenable and accessible to different ordered binding partners, potentially supporting their multi-functionality. The current study addresses this complex structure-functional interplay in IDPs using phase transition dynamics to conceptualize the underlying mechanism of their being distributed across degenerate structural states (conformational ensembles). For this purpose, extensive molecular dynamics simulations have been done and the data analyzed from a statistical physics perspective. A major emphasis has been put on the plausible scope of self-organized criticality (SOC) to be implemented in the dynamics of the complex system of IDPs relating their conformational degeneracy to their potential multi-functionality. In accordance with the transient nature of salt-bridge dynamics, the study further uses it as a probe to investigate the scope of the proposed criticality in the conformational phase transition among self-similar groups in IDPs. The results reveal scale-invariant self-similar fractal geometries in structural conformations of different IDPs. The study should also be beneficial for the structural tinkering of bio-medically relevant IDPs in the course of the design of biotherapeutics against them.