Crystallization of the first three domains of the human insulin-like growth factor-1 receptor

Abstract

The insulin-like growth factor-1 receptor (IGF-1R) is a tyrosine kinase receptor of central importance in cell proliferation. A fragment (residues 1- 462) comprising the L1-cysteine rich-L2 domains of the human IGF-1R ectodomain has been overexpressed in glycosylation-deficient Lec8 cells and has been affinity-purified via a c-myc tag followed by gel filtration. The fragment was recognized by two anti-IGF-1R monoclonal antibodies, 24-31 and 24-60, but showed no detectable binding of IGF-1 or IGF-2. Isocratic elution of IGF-1R/462 on anion-exchange chromatography reduced sample heterogeneity, permitting the production of crystals that diffracted to 2.6 Å resolution with cell dimensions a = 77.0 Å, b = 99.5 Å, c = 120.1 Å, and space group P212121.