the LRR-OLF interface area appears relatively small with respect to the high affinity of the interaction (Chen et al., 2013). Therefore, beyond the solvent-inaccessibility of interface residues, some key structural features, such as the strong electrostatic surface complementary between the concave face of FLRT3-LRR and globular LPHN3-OLF, are at play in the stability of the OLF-LRR association. Our mutational analyses point to the FLRT3-LRR Phe160. Indeed, its central position within the interface, its high level of buried area (Table S3, related to Figure 4) and the observed affinity decrease in Phe160Ala make this position as a “hot spot” for the interaction (Bogan and Thorn, 1998). Regarding the ADHD-linked mutation, this residue is not conserved in the LPHN family and the Ala313 Ser mutation does not affect FLRT3 binding, suggesting that it may simply represent a benign SNP.
