FIG. 2.

Predicted structure of GCP-2/CXCL6 in relation to antibacterial activity. (A) Predictive model based on known structures of other members of the chemokine family. The NH₂ terminus, most likely, is an unstructured region followed by three antiparallel β-sheets that are held together by disulfide bonds involving the cysteines of the CXC motif (yellow). The COOH terminus is presumably an α-helix (purple). (B) The putative COOH-terminal α-helix (amino acids 56 to 77) has an amphipathic structure where hydrophobic (blue) and hydrophilic (white/yellow) amino acids are arranged in a polarized fashion. (C) The amphipathic character of the COOH terminus is further elucidated by depicting it as a helical wheel, giving a view of a helix from a protein sequence, looking down the axis of the helix.