The Ribbons that Bind

In this image, a fragment of the antibody Erbitux (cetuximab) binds to its target, a fragment of epidermal growth factor receptor (EGFR).  The blue ribbon at the top is the backbone of the EGFR fragment, and the red and gray ribbons at the bottom are the backbone of the antibody fragment.

The licorice sticks and the balls in the central portion represent protein side-chains making close interactions between the antigen, EGFR, and the antibody, with the balls representing a mutation that researchers designed using computers.

Credit: Shaun Lippow, Massachusetts Institute of Technology