Fig. 2

Crystallographic analysis of the BCMA–nanobody complexes. a Surface and cartoon representation of the crystal structure of Nb1 in complex with BCMA_ECD. Nb1 is colored blue and BCMA green. The putative N-linked glycosylation sites of BCMA (N42) are highlighted in pink. Inset, electron density (2F_O − F_C map contoured at 1 σ) of the amino (N)-terminal region of BCMA is shown as gray mesh. b Cartoon representation of the Nb1 complex with the complementarity-determining region (CDR) 1 of Nb1 colored in green, CDR2 in cyan, and CDR3 in orange while framework region (FR) 1 in purple blue, FR2 in pink, FR3 in yellow, and FR4 in marine. c Open-book views of BCMA complexes showing interfaces with antibodies and ligands. Interface residues are outlined in red or orange. d, e Surface and cartoon representation of the crystal structure of Nb2 in complex with BCMA_ECD. Nb2 chains are colored wheat and light wheat while BCMA molecules pale green and praseodymium green for the observed two pairs in the asymmetric unit (d). The putative N-linked glycosylation sites of BCMA are highlighted. For the cartoon representation in (e), the Nb2 CDRs and FRs are color-coded as in (b). f An open-book view showing the interface between Nb2 and BCMA_ECD. The interface residues are outlined in red