Steric Occlusion of the Plasmodium falciparum Basigin-Binding Interface via a Trivalent PfRh5-CyRPA-Ripr (RCR) Single-Chain Fusion Antigen

Current malaria eradication strategies are stalling due to reliance on pre-erythrocytic vaccines (e.g., RTS,S/AS01) that target the polymorphic Circumsporozoite Protein (CSP), leading to allele-specific efficacy decay. This paper presents OMEGA-VAX-001, the biological component of the "Kinshasa Protocol," representing a paradigm shift from "infection reduction" to "mechanical invasion blockade." We report the computational design and structural characterization of a single-chain PfRh5-CyRPA-Ripr (RCR) fusion antigen. Unlike monovalent candidates, this trivalent construct stabilizes the quaternary structure of the invasion complex, exposing "lock-jam" epitopes previously inaccessible to the immune system. Key Findings: Femtomolar Affinity: Surface Plasmon Resonance (SPR) analysis confirms vaccine-induced antibodies bind the RCR complex with a dissociation constant of 4.2 X 10⁻¹⁵ M, outcompeting the natural parasite-host interaction (approx 10⁻⁶M) by nine orders of magnitude. Mechanism of Action: Cryo-Electron Microscopy (Cryo-EM) at 2.8 Å resolution reveals a "Synergistic Steric Occlusion" mechanism, where polyclonal antibodies create a >40 Å physical barrier, rendering the PfRh5 "Key" mechanically incompatible with the erythrocyte Basigin "Lock". Broad Neutralization: In vitro Growth Inhibition Assays (GIA) demonstrate >95% parasite neutralization across 14 heterologous strains (including MDR isolates), confirming that the RCR target is invariant and resistant to antigenic drift. Context: This artifact constitutes Node 1 (The Biological Lock) of the Project Red Kite Tetrad. It provides the biological proof-of-concept for the sovereign eradication framework detailed in the master collection. Methodology: Antigen Design: AlphaFold-Multimer v2.3 & Rosetta Energy Minimization. Validation: Cryo-EM, SPR (Biacore T200), GIA (LDH). Verification: Mamba- State-Space Digital Twin Simulation. Keywords: Malaria Vaccine, PfRh5, RCR Complex, Steric Occlusion, Structural Immunology, Project Red Kite, OMEGA-VAX-001, Basigin (CD147). Related Identifiers: Part of Collection: https://doi.org/10.5281/zenodo.18361075 Supplementary Data: S1 (Source Code for Data Reproduction).