Angiopoietins have distinct modular domains essential for receptor binding, dimerization and superclustering. - Davis S; Papadopoulos N; Aldrich TH; Maisonpierre PC; Huang T; Kovac L; Xu A; Leidich R; Radziejewska E; Rafique A; Goldberg J; Jain V; et al. (Nature structural biology, 2003)