Probing the Structural Dynamics of the Unbound MAX Protein: Insights from Well-Tempered Metadynamics.

One of most relevant challenges in tumorigenesis is the association of MYC and MAX proteins, whose related cancers remain undrugged. In particular, the disordered regions shown by those oncogenes make their structural characterization and the development of new drugs a truly hard task. To address these challenges, we employed the enhanced-sampling well-tempered metadynamics method to systematically explore the conformational space of the unbound MAX protein. Our results revealed, for the first time, a well-defined and thermodynamically favorable conformation of monomeric MAX. This is a remarkable finding, as it demonstrates that regions of MAX previously considered persistently disordered are capable of adopting stable, folded structures under specific conditions. Moreover, our findings also suggest that the metastable structural motifs observed in this work may harbor druggable sites, particularly relevant for strategies aiming to target MAX directly or to disrupt its interaction with MYC, thereby modulating oncogenic signaling pathways. The present study establishes a new structural framework for understanding the dynamics of MAX and provides a foundation for future structure-based drug design targeting the MYC/MAX axis. Finally, our work offers a strategic blueprint for investigating similarly challenging drug targets.