6pbw
Crystal structure of Fab667 complex
Structural highlights
FunctionCSP_PLAF7 Essential sporozoite protein (PubMed:29554084, PubMed:32150583). In the mosquito vector, required for sporozoite development in the oocyst, migration through the vector hemolymph and entry into the vector salivary glands (By similarity). In the vertebrate host, required for sporozoite migration through the host dermis and infection of host hepatocytes (PubMed:29554084, PubMed:32150583). Binds to highly sulfated heparan sulfate proteoglycans (HSPGs) on the surface of host hepatocytes (By similarity).[UniProtKB:P23093][1] [2] In the vertebrate host, binds to highly sulfated heparan sulfate proteoglycans (HSPGs) on the surface of host hepatocytes and is required for sporozoite invasion of the host hepatocytes.[UniProtKB:P23093] Publication Abstract from PubMedLasting protection has long been a goal for malaria vaccines. The major surface antigen on Plasmodium falciparum sporozoites, the circumsporozoite protein (PfCSP), has been an attractive target for vaccine development and most protective antibodies studied to date interact with the central NANP repeat region of PfCSP. However, it remains unclear what structural and functional characteristics correlate with better protection by one antibody over another. Binding to the junctional region between the N-terminal domain and central NANP repeats has been proposed to result in superior protection: this region initiates with the only NPDP sequence followed immediately by NANP. Here, we isolated antibodies in Kymab mice immunized with full-length recombinant PfCSP and two protective antibodies were selected for further study with reactivity against the junctional region. X-ray and EM structures of two monoclonal antibodies, mAb667 and mAb668, shed light on their differential affinity and specificity for the junctional region. Importantly, these antibodies also bind to the NANP repeat region with equal or better affinity. A comparison with an NANP-only binding antibody (mAb317) revealed roughly similar but statistically distinct levels of protection against sporozoite challenge in mouse liver burden models, suggesting that junctional antibody protection might relate to the ability to also cross-react with the NANP repeat region. Our findings indicate that additional efforts are necessary to isolate a true junctional antibody with no or much reduced affinity to the NANP region to elucidate the role of the junctional epitope in protection. Structure and mechanism of monoclonal antibody binding to the junctional epitope of Plasmodium falciparum circumsporozoite protein.,Oyen D, Torres JL, Aoto PC, Flores-Garcia Y, Binter S, Pholcharee T, Carroll S, Reponen S, Wash R, Liang Q, Lemiale F, Locke E, Bradley A, King CR, Emerling D, Kellam P, Zavala F, Ward AB, Wilson IA PLoS Pathog. 2020 Mar 9;16(3):e1008373. doi: 10.1371/journal.ppat.1008373. PMID:32150583[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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