We previously reported that the LG4 domain of the laminin α4 chain is responsible for high-affinity heparin binding. To specify the amino acid residues involved in this activity, we produced a series of α4 LG4-fusion proteins in which each of the 27 basic residues (arginine, R; histidine; lysine, K) were replaced one by one with alanine (A). When the effective residues R1520A, K1531A, K1533A, and K1539A are mapped on a structural model, they form a track on the concave surface of the β-sandwich, suggesting that they interact with adjacent sulfate groups along the heparin chain. Whereas low-affinity heparin-binding sites of other LG domains have been located at the top of the β-sheet sandwich opposite the N and C termini, the residues for high-affinity heparin binding of α4 LG4 reveal a new topological area of the LG module. © 2003 Elsevier Ltd. All rights reserved.
Yamashita, H., Beck, K., & Kitagawa, Y. (2004). Heparin Binds to the Laminin α4 Chain LG4 Domain at a Site Different from that Found for Other Laminins. Journal of Molecular Biology, 335(5), 1145–1149. https://doi.org/10.1016/j.jmb.2003.11.047