Fig. 1

Model of humanized β-CTF bound to BACE1 and western blot analysis of mouse, rat and human APP. a Sequence alignment between the peptide inhibitor used in the crystal structure 5MCQ and the humanized β-CTF. Green: the three amino acids different between the human and rodent APP sequence. b The BACE structure is presented with its flap [22] in yellow and the 10S loop in orange; a model of rodent Aβ peptide is fitted. c Shows the same structure but now modelled with the humanized β-CTF. Two extra interactions between the G676R of the peptide and residue E326 and F681Y and residue N294 of BACE can be noted. d Western blot analysis of APP protein in the cerebrum of WT mouse (M), WT rat (R) and human (H), (n = 6). The B63 antibody, raised against the C-terminal part of APP, detects both full length APP (FL APP) and C-terminal fragments (CTF, longer exposure). β-ACTIN was used as the loading control. e Intensity-based quantification of full length APP, with values normalized to the human sample (n = 6, mean ± SD, **p = 0.0063 α-CTF/FL APP, **p = 0.0023 CTF/FL APP, *** p = 0.0002, ****p < 0.0001, One-Way ANOVA, Turkey post-hoc test)