Video 1
Stability of the closed-angle conformation of L-selectin. Comparison of the simulated structure of L-selectin (cyan) with the crystal structures of L-selectin (blue) and P-selectin (red). The P-selectin structure (PDB 1G1S; Somers et al., 2000) has an open interdomain angle. In comparison, the L-selectin structure has a closed interdomain angle, which aligns very well with the closed-angle P-selectin structure (PDB 1G1Q; Somers et al., 2000). The lectin domains (residues 1-120) of the crystal structures of L- and P-selectin, and of the simulated L-selectin structure in each frame, were aligned through the backbone atoms, whereas the EGF domains were unconstrained. Over the 6-ns simulation time, the simulated L-selectin structure was observed to fluctuate slightly around the crystal structure of L-selectin. The green sphere depicts the Ca2+ ion coordinated by the lectin domain. The video was generated with VMD software (Molecular Graphics; Humphrey et al., 1996.)