Figure 3.

(A, B) Representative structures of the two different ¹⁻²FNIII forms present in the structure calculation. Occupancy of form A in the final ensemble was 78%, whereas that of form B was 22%. Side chains for two residues, K669 and D767, involved in an electrostatic interaction in form A but not form B, are shown. D767 is also involved in electrostatic interactions with K672 in population A, and participates in an extended hydrogen bond and electrostatics network on the ¹FNIII binding interface of ²FNIII. The interdomain linker is schematically represented as a dashed line. (C, D) ¹⁻²FNIII structure. Shown here are: the final 39-structure ensemble of ¹⁻²FNIII structures displaying (C) or omitting (D) the flexible ¹FNIII–²FNIII linker. Secondary structure elements are colored cyan and purple for ¹FNIII and ²FNIII, respectively.