Figure 1.

Design of N-terminal deletion mutants of FZD₆. A, an overlay of the full-length SMO structure (PDB code 5V57) and the XWNT8-mFZD₈-CRD structure (PDB code 4F0A) to visualize domain arrangement in FZDs. XWNT8, red/firebrick; CRD, yellow; linker region, green; 7TM core, gray. B, schematic of constructs for full-length human FZD₆ (FL), ΔCRD-FZD₆ (ΔCRD), and ΔLinker-FZD₆ (ΔLinker). All three constructs carry an N-terminal FLAG and a C-terminal His tag. Numbers refer to amino acid numbering in the human FZD₆ (UniProtKB accession number O60353 (FZD6_HUMAN)). C, the amino acid sequence defines the N-terminal amino acid of ΔCRD-FZD₆ (Asp-156) and ΔLinker-FZD₆ (Ala-182). Structures were rendered using PyMOL (PyMOL Molecular Graphics System, version 2.0, Schrödinger, LLC).