Figure 3.

A) Ribbon diagram of one monomer of fused 4-OT. The α- and β-domains are labeled and colored in two shades of green. The linker loop is labeled and colored in bright blue. B) The fused 4-OT trimer, color coded and chains defined: monomer A in green (flipped monomer), monomer B in teal and monomer C in taupe. Interfaces defined between each monomer. C) Schematic of oligomerization arrangement of fused 4-OT. Color scheme is the same as in 3B and the position of Pro-1 is shown. D) Ribbon representation of the C. aurantiacus heterohexamer 4-OT with each interface defined.²⁰ E) Ribbon representation of Linker 2 (a fused 4-OT) with each interface labeled.¹⁸ All interfaces are identical alpha-beta interfaces. F) In the same orientation as E, schematic of N-terminal β-strand containing Pro-1 of Linker 2, all monomers are symmetrical.