6jbt
Complex structure of toripalimab-Fab and PD-1
Structural highlights
DiseasePDCD1_HUMAN Systemic lupus erythematosus;Multiple sclerosis. Systemic lupus erythematosus 2 (SLEB2) [MIM:605218: A chronic, relapsing, inflammatory, and often febrile multisystemic disorder of connective tissue, characterized principally by involvement of the skin, joints, kidneys and serosal membranes. It is of unknown etiology, but is thought to represent a failure of the regulatory mechanisms of the autoimmune system. The disease is marked by a wide range of system dysfunctions, an elevated erythrocyte sedimentation rate, and the formation of LE cells in the blood or bone marrow. Note=Disease susceptibility is associated with variations affecting the gene represented in this entry.[1] FunctionPDCD1_HUMAN Inhibitory cell surface receptor involved in the regulation of T-cell function during immunity and tolerance. Upon ligand binding, inhibits T-cell effector functions in an antigen-specific manner. Possible cell death inducer, in association with other factors.[2] Publication Abstract from PubMedMonoclonal antibody (mAb)-based blockade of programmed cell death 1 (PD-1) or its ligand to enable antitumor T-cell immunity has been successful in treating multiple tumors. However, the structural basis of the binding mechanisms of the mAbs and PD-1 and the effects of glycosylation of PD-1 on mAb interaction are not well understood. Here, we report the complex structure of PD-1 with toripalimab, a mAb that is approved by China National Medical Products Administration as a second-line treatment for melanoma and is under multiple Phase 1-Phase 3 clinical trials in both China and the US. Our analysis reveals that toripalimab mainly binds to the FG loop of PD-1 with an unconventionally long complementarity-determining region 3 loop of the heavy chain, which is distinct from the known binding epitopes of anti-PD-1 mAbs with structural evidences. The glycan modifications of PD-1 could be observed in three potential N-linked glycosylation sites, while no substantial influences were detected to the binding of toripalimab. These findings benefit our understanding of the binding mechanisms of toripalimab to PD-1 and shed light for future development of biologics targeting PD-1. Atomic coordinates have been deposited in the Protein Data Bank under accession code 6JBT. Glycosylation-independent binding of monoclonal antibody toripalimab to FG loop of PD-1 for tumor immune checkpoint therapy.,Liu H, Guo L, Zhang J, Zhou Y, Zhou J, Yao J, Wu H, Yao S, Chen B, Chai Y, Qi J, Gao GF, Tan S, Feng H, Yan J MAbs. 2019 May/Jun;11(4):681-690. doi: 10.1080/19420862.2019.1596513. Epub 2019, Apr 19. PMID:30892132[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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