Title :

Theoretical Physics of Disordered Proteins reveal Biological Insights

Abstract :

Protein sequence -- encoding the unique folded structure and consequently function -- plays a profound role in biological information processing. This central notion, however, appears to be at odds with Intrinsically Disordered Proteins (IDP)s that lack unique folded structure. In spite of being disordered and interconverting beween different conformations, IDPs have specific conformational features and critical function. The clues to conformation, function -- and their relation, if any -- must be in the sequence. But how do we decipher this code from the sequence ? Recent advances in heteropolymer theory -- based on a coarse grain Hamiltonian -- unmasked the existence of several elegant mathematical formulae hidden in the sequence that describe IDPs conformational features. We will focus on the set of these formulae/metric that arise specifically from the placement of charges -- and not just their total number -- in the protein sequence. These simple mathematical relations reveal many surprises in IDP conformation and yield biological insights. For example, they show how IDPs can induce collapse and swelling at different length scales. Extending this, we can detect role of phosphorylation at specific hot spots to induce drastic conformation changes, even far from the modification sites, reminiscing `action at a distance'. These information rich molecular blueprints can even help us identify functionally similar IDPs, not possible by traditional sequence alignment tools used for folded proteins.