6SNY

Synthetic mimic of an EPCR-binding PfEMP1 bound to EPCR

6SNY の概要

• エントリーDOI: 10.2210/pdb6sny/pdb
• 分子名称: Synthetic EPCR binding protein, Endothelial protein C receptor, alpha-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (6 entities in total)
• 機能のキーワード: pfemp1 epcr vaccine immunogen, immune system
• 由来する生物種: synthetic construct; 詳細
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 64103.24

構造登録者

Barber, N.M.,Higgins, M.K. (登録日: 2019-08-27, 公開日: 2019-09-04, 最終更新日: 2024-10-16)

主引用文献

Barber, N.M.,Lau, C.K.Y.,Turner, L.,Watson, G.,Thrane, S.,Lusingu, J.P.A.,Lavstsen, T.,Higgins, M.K.
Structure-Guided Design of a Synthetic Mimic of an Endothelial Protein C Receptor-Binding PfEMP1 Protein.
Msphere, 6:-, 2021

PubMed Abstract: Structure-guided vaccine design provides a route to elicit a focused immune response against the most functionally important regions of a pathogen surface. This can be achieved by identifying epitopes for neutralizing antibodies through structural methods and recapitulating these epitopes by grafting their core structural features onto smaller scaffolds. In this study, we conducted a modified version of this protocol. We focused on the PfEMP1 protein family found on the surfaces of erythrocytes infected with A subset of PfEMP1 proteins bind to endothelial protein C receptor (EPCR), and their expression correlates with development of the symptoms of severe malaria. Structural studies revealed that PfEMP1 molecules present a helix-kinked-helix motif that forms the core of the EPCR-binding site. Using Rosetta-based design, we successfully grafted this motif onto a three-helical bundle scaffold. We show that this synthetic binder interacts with EPCR with nanomolar affinity and adopts the expected structure. We also assessed its ability to bind to antibodies found in immunized animals and in humans from malaria-endemic regions. Finally, we tested the capacity of the synthetic binder to effectively elicit antibodies that prevent EPCR binding and analyzed the degree of cross-reactivity of these antibodies across a diverse repertoire of EPCR-binding PfEMP1 proteins. Despite our synthetic binder adopting the correct structure, we find that it is not as effective as the CIDRα domain on which it is based for inducing adhesion-inhibitory antibodies. This cautions against the rational design of focused immunogens that contain the core features of a ligand-binding site of a protein family, rather than those of a neutralizing antibody epitope. Vaccines train our immune systems to generate antibodies which recognize pathogens. Some of these antibodies are highly protective, preventing infection, while others are ineffective. Structure-guided rational approaches allow design of synthetic molecules which contain only the regions of a pathogen required to induce production of protective antibodies. On the surfaces of red blood cells infected by the malaria parasite are parasite molecules called PfEMP1 proteins. PfEMP1 proteins, which bind to human receptor EPCR, are linked to development of severe malaria. We have designed a synthetic protein on which we grafted the EPCR-binding surface of a PfEMP1 protein. We use this molecule to show which fraction of protective antibodies recognize the EPCR-binding surface and test its effectiveness as a vaccine immunogen.

PubMed: 33408232
DOI: 10.1128/mSphere.01081-20

実験手法

X-RAY DIFFRACTION (3.11 Å)