Fig. 2: Structural characterization of VUN701.

a NMR structural ensemble of VUN701 (PDB: 8UEK) with the three nanobody complimentary-determining regions (CDRs) colored. b Representative GPCR-targeting nanobodies belonging to the three CDR3 conformations: short (left), extended (middle), and folded (right) — complimentary-determining regions colored as in A. Nanobody names and PDB IDs are displayed below structures. c Plot of all 1962 nanobody structures in the PDB, colored based on the distribution of defined CDR3 conformations. Of the 1962 structures, there are 662 non-redundant structures. PDB IDs of each nanobody structure are placed along the outside of the pinwheel, sorted by their CDR3 type. Redundant nanobody structures are placed on the same line. d Plot of all 54 GPCR-targeting nanobody structures in the PDB, colored based on the distribution of CDR3 conformations. 16 represent non-redundant structures. PDB IDs of each nanobody structure are placed along the outside of the pinwheel, sorted by their CDR3 type with their name, GPCR target, and surface epitope. Redundant nanobody structures are placed on the same line. e ACKR3 BRET-based β-arrestin2 assay with increasing CXCL12 (gray) or competition assay of 3.3 nM CXCL12 with increasing WT VUN701 (black), and CDR variants ∆CDR1 (blue), ∆CDR2 (green), and ∆CDR3 (red) illustrating the alteration in IC₅₀ due to deletion of CDR important contacts. N = 3 biologically independent experiments plotted as mean +/- SEM. Source data are provided as a Source Data file.