5mi0
From Proteopedia
A thermally stabilised version of Plasmodium falciparum RH5
Structural highlights
FunctionRH5_PLAF7 Essential for the invasion of host erythrocytes by blood stage merozoites (PubMed:25583518, PubMed:27374406, PubMed:25296023, PubMed:22080952, PubMed:18827878, PubMed:19000690, PubMed:31204103, PubMed:28186186, PubMed:28409866). By binding P113 at the surface of the merozoite and human BSG/basigin on the erythrocyte membrane, leads to the establishment of a tight junction between the merozoite and host erythrocyte membranes (PubMed:25583518, PubMed:27374406, PubMed:25296023, PubMed:22080952, PubMed:28186186). In addition, the interaction with BSG results in BSG dimerization which triggers an increase in intracellular Ca(2+) in the erythrocyte (PubMed:27374406, PubMed:28409866). This essential step leads to a rearrangement of the erythrocyte cytoskeleton required for the merozoite invasion (PubMed:28409866).[1] [2] [3] [4] [5] [6] [7] [8] [9] Publication Abstract from PubMedMany promising vaccine candidates from pathogenic viruses, bacteria, and parasites are unstable and cannot be produced cheaply for clinical use. For instance, Plasmodium falciparum reticulocyte-binding protein homolog 5 (PfRH5) is essential for erythrocyte invasion, is highly conserved among field isolates, and elicits antibodies that neutralize in vitro and protect in an animal model, making it a leading malaria vaccine candidate. However, functional RH5 is only expressible in eukaryotic systems and exhibits moderate temperature tolerance, limiting its usefulness in hot and low-income countries where malaria prevails. Current approaches to immunogen stabilization involve iterative application of rational or semirational design, random mutagenesis, and biochemical characterization. Typically, each round of optimization yields minor improvement in stability, and multiple rounds are required. In contrast, we developed a one-step design strategy using phylogenetic analysis and Rosetta atomistic calculations to design PfRH5 variants with improved packing and surface polarity. To demonstrate the robustness of this approach, we tested three PfRH5 designs, all of which showed improved stability relative to wild type. The best, bearing 18 mutations relative to PfRH5, expressed in a folded form in bacteria at >1 mg of protein per L of culture, and had 10-15 degrees C higher thermal tolerance than wild type, while also retaining ligand binding and immunogenic properties indistinguishable from wild type, proving its value as an immunogen for a future generation of vaccines against the malaria blood stage. We envision that this efficient computational stability design methodology will also be used to enhance the biophysical properties of other recalcitrant vaccine candidates from emerging pathogens. One-step design of a stable variant of the malaria invasion protein RH5 for use as a vaccine immunogen.,Campeotto I, Goldenzweig A, Davey J, Barfod L, Marshall JM, Silk SE, Wright KE, Draper SJ, Higgins MK, Fleishman SJ Proc Natl Acad Sci U S A. 2017 Jan 17. pii: 201616903. doi:, 10.1073/pnas.1616903114. PMID:28096331[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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