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New tools for autoimmune kidney disease: Design of antigen binding proteins against the thrombospondin type‐1 containing domain 7A
Author(s) -
Stoddard Serena Daniella,
Stoddard Shana Victoria
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.472.11
Subject(s) - antigen , thrombospondin , homology modeling , epitope , autoantibody , immune system , autoimmune disease , computational biology , chemistry , in silico , docking (animal) , binding selectivity , antibody , biology , immunology , medicine , biochemistry , gene , nursing , metalloproteinase , matrix metalloproteinase , enzyme
Idiopathic membranous nephritis, (IMN) is an autoimmune disease (AD) affecting the kidney. Conventional treatment for AD uses immunosuppressive medicines that suppress the entire immune system, rather than target specific autoimmune disorder antibodies. This causes patients to become immunocompromised, and at risk of not being able to fight off common infections. A more specific therapy to treat AD is needed to prevent the suppression of the entire immune system. Thus the goal of this work was to develop antigen binding proteins (ABP) which could prevent autoantibody binding to the antigen of interest in an AD. ABP targeting the thrombospondin type‐1 containing domain 7A (THSD7A) antigen of IMN were developed. Domain 2 of THSD7A was used as the target site for binding. These designs were carried out through in silico mutagenesis of template monobody candidates. Homology modeling of designed proteins was performed using the Phyre2 server for all ABP. The Rosetta docking2 protocol was used to determine strength of protein‐protein interactions between the ABP and domain 2 of THSD7A. Molecular interactions were evaluated to determine which mutations strengthened binding of the ABP to the THSD7A. Several mutations were shown to improve overall binding compared to the template monobody (3UYO) which was found to have an interface score of −2.511, measured in Rosetta energy units (REU). The most promising binding efficiency scores and placement of an ABP was shown to be the C‐side location of the 3UYO ABP template. Introduction of an electrostatic interaction through the single point mutation S88D, produced an interface score of −5.557 REU. The four point mutation G43W, T72R, S88D, S91D introducing three electrostatic interactions, one hydrophobic interaction, resulted in an interface score of −4.793 REU. Currently protein expression and experimental testing is underway to evaluate binding in vitro . This work will assist in the design of antigen specific therapies for AD, leading to a more targeted therapeutic suppression of the immune system. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .