Fig. 1: Summary of effects of PS1 FAD mutations on enzyme-substrate interactions of the APP bound γ-secretase complex. | Communications Biology

Fig. 1: Summary of effects of PS1 FAD mutations on enzyme-substrate interactions of the APP bound γ-secretase complex.

From: Effects of presenilin-1 familial Alzheimer’s disease mutations on γ-secretase activation for cleavage of amyloid precursor protein

Fig. 1

a Cryo-EM structure of γ-secretase complex with APP bound (PDB: 6IYC) and locations of six PS1 FAD mutation residues (red spheres). The four components of γ-secretase are Nicastrin (NCT, green), Presenilin-1 (PS1, teal), Aph-1 (yellow) and Pen-2 (magenta). APP is shown in orange. b Anti-FLAG immunoblots and quantification of total AICD (black), AICD50-99 (red), and AICD49-99 (blue)-FLAG levels generated from the ε cleavage of APP by the WT and FAD mutants of γ-secretase by densitometry. Purified C100-FLAG at a range of known concentrations was used to generate a standard curve. c MALDI-TOF mass spectrometry (MS) detection of AICD50-99 and AICD49-99 products generated from the ε cleavage of APP by the WT and PS1 FAD mutants of γ-secretase. T-tests were performed, and the resulting p values were added along with the ratios to highlight the significance of the ratios determined for the PS1 FAD mutants. d–j 2D free energy profiles of the distance between PS1 residues D257 (atom Cγ) and D385 (atom Cγ) and distance between PS1 residue D385 (protonated oxygen) and APP residue L49 (carbonyl oxygen) in the WT (d) and P117L (e), I143T (f), L166P (g), G384A (h), L435F (i), and L286V (j) FAD mutants of APP bound γ-secretase. The low-energy conformational states are labeled “Active”, “Inhibited”, and “I1”–“I5”.

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