Docking model of LarA and LarB1. Model manually generated using
FoldIt with homology models, BLI data, and cross-linking data as distance
restraints. AzF constructs analyzed are shown in red, and corresponding
regions of cross-linking are shown in orange. LarB1 is shown in green,
LarA leader peptide residues 8–26 are shown in magenta, and
LarA core peptide residues 27–35 are shown in cyan. (A) LarB1
homology model after LarA docking (LarA hidden). Note the shift of
the β1 and β2 strands as compared to the homology model
before docking (Figure 5C). (B) Predicted interaction from bioinformatics analysis between
LarA Y10 (dark gray) and LarB1 D69 (light gray); LarA F21Z cross-linked
to LarB1 Y28. (C) LarB1 Y28Z cross-linked to the Y32–R33 region
of LarA. (D) LarB1 Q30Z cross-linked to the Q29–R33 region
of LarA. (E) LarB1 Y16Z and LarB1 V19Z both cross-linked to the T24–A26
region of LarA. The LarB1 V19Z restraint could not be satisfied, likely
because substitution of V19, a buried hydrophobic residue, with the
larger AzF caused a structural change to LarB1. (F) LarA W35Z cross-linked
to two regions, LarB1 Y16 and LarB1 A35–A36, that are far apart
in amino acid sequence but close together in space.