Journal: Acta Pharmaceutica Sinica. B
Article Title: Evolution-guided design of mini-protein for high-contrast in vivo imaging
doi: 10.1016/j.apsb.2025.07.015
Figure Lengend Snippet: Characteristics of designed BindHer protein. (A) Sequence alignments of BindHer (Design.05) with ZHER2:342, ABY-025, and wild-type Z-domain. Conserved residues are indicated by “:”, yellow highlights mutated residues against Z-domain, and blue stars mark the core interface binding residues (R10, Y13, W14, R28, R32, Y35) with HER2. (B) Structural alignment of the I-TASSER (green) and AlphaFold2 (orange) prediction of BindHer. (C) Structure overlay of AlphaFold2 model of BindHer on ABY-025 in complex with HER2. The right panel shows the zoom-in of the ABY-025 structure, where the core interface residues to HER2 ECD are displayed in sticks. For reference, the Fab fragments of therapeutic monoclonal antibodies trastuzumab (red) and pertuzumab (cyan) are shown binding HER2 epitopes, which are distant from the binding regions of BindHer and ABY-025.Right showed that the core interface binding residues (R10, Y13, W14, R28, R32, Y35) with HER2. (D) Distribution of surface hydrophobic networks, with orange indicating hydrophobic residues of ABY-025 and BindHer. (E) Bis-ANS fluorescence of ABY-025 and BindHer at different concentration, with error bar representing 95% confidence interval (CI) from three technical replicates, ∗∗∗∗ P < 0.0001. (F) The ABY-025 and BindHer structures are depicted in the electrostatic surface view, with red representing potentials of –5 KTe –1 and blue representing potentials of 5 kTe -1 . The electrostatic potentials were computed using PyMol's APBS module. (G) Comparison of positive, negative and net charges of ABY-025 and BindHer. The secondary structure, surface hydrophobicity, and surface electrostatic potentials of each protein in the plot were visualized using PyMol and UCSF ChimeraX.
Article Snippet: Recombinant Human HER2 ECD (1004-HCCH, Sino Biological) was immobilized (∼2000 resonance units) on a CM5 sensor chip (BR-1000-12, GE Life Sciences) and analyzed using a Biacore instrument (Biacore X100, GE Life Sciences).
Techniques: Sequencing, Binding Assay, Bioprocessing, Fluorescence, Concentration Assay, Comparison