Fig. 1. TSP1 binding to versican. (A) TSP1 binding to immobilized full-length versican. Wells were coated using the indicated concentrations of versican, blocked with 3% BSA and incubated with 0.5 µg ml^–1 (1.1 nM) of [¹²⁵I]-TSP1 in buffers containing Ca²⁺ and Mg²⁺ for 3 hours at 37°C. Background values were subtracted from each data point (211.2±19.1). (B) Versican core protein contains an amino terminal hyaluronan-binding region containing an immunoglobulin and 2 Link protein modules (G1), a variably spliced glycosaminoglycan-attachment domain (GAG) and a C-terminal domain (G3) containing two epidermal growth factor-like repeat, a C-type lectin-like module and a complement regulatory protein-like module. (C) Binding of [¹²⁵I]-TSP1 to wells coated using 1 µg per well of versican was determined in the presence of the indicated concentrations of VG1. Results are normalized to net binding measured in the absence of VG1 (748.8±24.2 cpm). (D) Binding of [¹²⁵I]-TSP1 to wells coated with the indicated concentrations of VG1 in buffers containing Ca²⁺ and Mg²⁺ () or 5 mM EDTA () for 3 hours at 37°C. Background values were subtracted from each data point (137.3±13.2 and 87.2±9.6, respectively). All data are mean ± s.e.m. for quadruplicate determinations.