Conformational changes in OSCAR upon THP binding. Conformational changes in (A) OSCAR D1 and (B) OSCAR D2 upon binding DB316, shown by alignment of apo- and DB316-bound structures. The free OSCAR ectodomain is colored magenta; the structure of DB316-bound OSCAR ectodomain is colored cyan with its semitransparent surface in white; leading, middle, and trailing strands of DB316 are colored green, yellow, and gray, respectively. Leading and middle stands of DB316, which are not involved in binding OSCAR D2, are removed in panel B for clarity. Spatial relocation of interfacial residues are indicated by black arrows. The steric clash of free OSCAR Glu-139 with trailing chain Phe-8, when superimposing apo- and bound- structures, is indicated by a circle.