Figure 7.

Proposed structure of the identified peptide Ac‐TTAI‐NH₂ binding to AT. The peptide inserted into the lower part of A‐sheet (labelled in blue) of AT and interacted with its nearby residues. The NH and CO groups from the backbone of the incorporated peptide were hydrogen bonded to the backbones of adjacent strands 3 and 5 (residues in yellow) of AT (square panel on the left) and rendered the A‐sheet into a six‐stranded antiparallel β‐sheet. The circle on the upper right revealed the hydrogen bond (light green dashed line) between the N‐terminal Thr (P8) of peptide Ac‐TTAI‐NH₂ and Ser56. Additional hydrogen bonds derived from the acetyl group of peptide with the side chain of His334 (light green dashed line) and the backbone NH group of Lys335 (light green dashed line) were also illustrated. The circle on the lower right showed the hydrophobic side chain of Ile occupies and interacted with a pocket surrounding by residues of Val173, Glu175, Leu176, Ala183 and Lys331. The complex orientations in the two circle panels on the right were changed to better present the peptide‐protein interactions. Carbon, nitrogen and oxygen atoms were shown in white, light blue and red, respectively.