The Evolutionary Enigma of Intrinsically Disordered Proteins
The classical paradigm of molecular biology—Anfinsen's dogma—posits that a protein's amino acid sequence dictates a unique, stable three-dimensional structure, which in turn determines its biological function. For decades, this framework has underpinned the practice of molecular phylogenetics, where scientists infer evolutionary relationships by aligning protein sequences. By measuring the accumulation of mutations in these sequences over time, researchers construct phylogenetic trees that track the divergence of species and gene families. However, the discovery and widespread characterization of intrinsically disordered proteins (IDPs) and intrinsically disordered regions (IDRs) have introduced a profound challenge to this approach. IDPs, which lack a stable, rigid tertiary structure and instead exist as dynamic ensembles of interconverting conformations, frequently exhibit sequence similarity that defies traditional phylogenetic mapping. This decoupling of sequence similarity...