Overall structure of the single-chain chimeric β₃headpiece. (A) Diagram of the native and chimeric β₃ (cβ₃) constructs. The cβ₃-E2 construct was truncated at the I-EGF2 domain. (B) The 2 copies of cβ₃-E2 structure in the asymmetric unit. N-linked glycans are shown as sticks with green carbons, red oxygens, and blue nitrogens. Metal ions are shown as spheres. Disulfide bonds are blue sticks. (C) Structural alignment of the 2 cβ₃-E2 molecules in the asymmetric unit. (D) Structural comparison of the extended cβ₃-E2 structure (in red; disulfide bonds in blue) with the native β₃ structure (PDB 3FCS; in cyan; disulfide bonds in yellow). The 2 structures were aligned on the hybrid domain.