Figure 5.

Structurally Equivalent but Topologically Distinct β Helices Can Be Formed by Monomers and Entangled Trimers

(A) Bacteriophage T4 cell puncturing device (1k28, blue) and Bordetella pertussis virulence factor pertactin (1dab, green) superimposed with the matching β helix parts in orange and red, respectively.

(B) The monomeric chain of 1 dab (green).

(C) Single chain of the 1k28 trimer (blue).

(D) The three chains of the 1k28 trimer colored blue, red, and yellow, respectively.

(E) Cross-section of the 1k28 trimer.

(F) Cross-section of the superimposed 1k28 trimer (blue) and 1 dab monomer (green), with the matching parts in orange and red, respectively.

(G) Cross-section of the 1 dab monomer (green).