IMMUNOGLOBULIN-LIKE DOMAINS DEFINE THE NERVE GROWTH-FACTOR BINDING-SITE OF THE TRKA RECEPTOR

Nerve growth factor (NGF) is involved in the development and maintenan ce of the nervous system. NGF binds with high affinity to the extracel lular region of the tyrosine kinase receptor TrkA, This domain compris es leucine and cysteine rich motifs, followed by two immunoglobulin li ke (Ig-like) domains, We describe the expression and purification of r ecombinant Ig-like domains. Fluorescence and circular dichroism spectr oscopy show that the protein is folded into a compact globular structu re and contains mainly beta-sheet secondary structure. Recombinant pro tein binds to NGF and can inhibit NGF bioactivity both in vitro and in vivo.