RBX1-02

• Submission order: 2
• Score rank: 2
• Format: Mini-protein
• Primary state: 8Q7R functional state
• Design method: BindCraft backbone plus ProteinMPNN redesign
• Description: This functional-state mini-protein was prioritized because it is the most convincing E2-facing entry in the set, which keeps the submission from collapsing into a 4F52-only story. The working model targets a functional RBX1 conformation related to the E2-facing interface in the 8Q7R functional state, and follow-up refolds recovered compatible placements in the 4F52 main-face conformation, the 3RTR transfer-related conformation, and the 2LGV display-state conformation. The strongest parts of the metric profile are 18 binder-side residues participating in the modeled interface, a contact patch that reaches 9 RBX1 residues, moderate RBX1 surface coverage of 0.500, high interface confidence at 0.902, strong developability at 0.939, and a composite ranking score of 7.3215. Novelty support is acceptable: the UniRef50 30-aa sliding-window screen is clear; no strong competing interaction is flagged in the off-target screen; the main caution is that the evidence is still computational and needs experimental confirmation; the full project rationale and design workflow are documented at https://github.com/tuna010101/RBX1-Binder-Design-Portfolio