Movie S1.

Key structural features for the GAG-free and GAG-bound CCL5 and CCL3. 0–3 s: Ribbon representation of CCL5 hexamer; CCL5 monomers are colored by chain. 4–10 s: Key residues involved in forming contacts at the interface between CCL5 dimers. 11–21 s: The open-ended CCL5 polymerization from 6mer to 10mer to 20mer. 22–30 s: Ribbon representation of CCL5 hexamer in complex with two synthetic heparin 8f chains. 31–36 s: Electrostatic potential of CCL5, which is colored from red (−10 kT) to blue (+10 kT). Heparin binds to the positively charged groove of CCL5. 37–45 s: Key residues involved in the CCL5–heparin interaction. 46–51 s: Ribbon representation of CCL3–synthetic heparin 8f. 52–56 s: Electrostatic potential of CCL3, which is colored from red (−1 kT) to blue (+1 kT). Heparin binds to the positively charged groove of CCL3. 57–64 s: Key residues involved in the CCL3–heparin interaction. 65–80 s: Morph of CCL3 decamer structure from that with N termini pointing inward to that with part N termini pointing outward. 81–84 s: The changes of electrostatic surface by the outward-pointing N termini of CCL3. 85–86 s: Electrostatic surface of CCL3 decamer with all N termini pointing inward. 87–90 s: Electrostatic surface of CCL3 decamer with 4 of 10 N termini pointing outward.