RBX1 contains a rigid RING-H2 domain (residues 40-108) and a fully disordered N-terminal region (residues 1-39). We designed binders targeting both regions, with the majority targeting the N-terminal disordered region — a challenging but functionally relevant area that has not been explored by conventional approaches.

Our design pipeline combines AF2 hallucination with ADFlip, which samples multiple target conformations during sequence optimization, allowing the designed binder to accommodate the inherent flexibility of the N-terminal region.

AF3 validation reveals that our binders induce folding of the disordered N-terminus: upon binding, the N-terminal region co-folds with the binder into a stable complex, with fraction_disordered dropping significantly and pLDDT increasing at the interface.