Fig 1: ProBDNF variants are similar in their binding to TrkB, p75NTR, sortilin and SorCS2.Representative sensorgrams are shown for 0–20 nM proBDNF FCR Val66 (a, c, e, and g) and FCR Met66 (b, d, f, and h) binding to their isolated receptor binding domains TrkBIg2, p75NTR ECD, sortilin LD and SorCS2 LD. Data was double referenced (RU) and plotted as a function of time. All the kinetic data were fitted to 1:1 Langmuir mathematical model and kinetic constants were calculated. KD denotes mean equilibrium dissociation constant. Mean constants for both Val66 and Met66 variants were not statistically different. Full kinetic constants are given in Table 1.