MOG is a novel binding partner for NGF. Structure and sequence alignment were performed in Chimera (Pettersen et al., 2004) using RCSB Protein Data Bank files 1WWW (TrkA; Wiesmann et al., 1999) and 1PKO (MOG; Breithaupt et al., 2003). (A) Individual 3D structures of TrkA (1WWW, chain X) and MOG (1PKO, chain A), and their overlay as generated by MatchMaker (Meng et al., 2006) included in Chimera. Both the extracellular domain of MOG and domain 5 of TrkA are Ig domains, hence the high degree of structural similarity. (B) Structure-based alignment of 1WWA chain X (TrkA, NGF binding domain) and 1PKO chain A (MOG). Shown are Clustal Conservation bars atop the sequences. Secondary structure features indicated are strands (green shading) and helices (yellow shading); the hexa-histidine tag of MOG is not shown. (C) Affinity pull-down of MOG-Fc with increasing concentrations of purified neurotrophins (0–2.0 µg/ml) show specific interaction between MOG and NGF. (D) NGF ELISA was performed with immobilized MOG-Fc. con, control.