Figure 4. The integrin binding site at the C-terminus of the laminin long arm. (A) The major integrin binding site on laminins is formed by the LG1 to LG3 domains and the extremity of coiled-coil fold formed by the α, β and γ chains. It is thought that the C-terminus of the γ chain is needed to stabilize a conformation of the LG1-LG3 trio compatible with integrin binding. (B) Representation of the amino acid sequences at the C-terminus of the three laminin γ chains. The γ1 and γ2 chains contains a glutamic acid residue (E, highlighted green) at the third position from the carboxyl termini. The residue is thought to be important for maintaining integrin binding activity of the structure shown in (A).⁵⁹ The laminin γ3 chain is shorter and lacks the glutamic acid residue at the same position. Recombinant fragment engineered as shown in A and containing the γ3 chain have no integrin binding activity.⁶⁰