Fig. 3: Biophysical examination of WT and mutant TP53.
From: Transcript errors generate amyloid-like proteins in human cells
A A transcription error (Tr) was identified in a TP53 transcript that substitutes a uracil for a cytosine base, resulting in a serine (S) to phenyl-alanine (F) mutation at residue 149. B,C Predicted structure of WT (B) and mutant TP53 (C). D Transmission electron microscopy showed little or no aggregates of WT TP53, while TP53S149F induces large protein aggregates (E). These experiments were performed 3–6 times with similar results. F,G Congo-red birefringence under polarized light indicates that TP53S149F forms amyloid fibrils (G), while WT TP53 does not (F). H After addition of 1% TP53S149F to a solution of WT TP53 (v/v), the WT solution generated countless aggregates. This experiment was performed 3 times with similar results. I–K Dynamic light scattering, which can be used to determine the radius of protein particles, indicates that WT TP53 is primarily in a monomeric form (I), while mutant TP53 consists of aggregates greater than 1000 nm (J). After 2% TP53S149F is added to a solution of WT TP53 (v/v), a large amount of TP53 aggregates emerges (K). L TP53S149F aggregates into a variety of structures. M TP53 aggregates were sonicated to create a seed solution of particles that are around 0.1 µm in size, which equates to 800-1000 proteins. (N) WT TP53 solution shows no apparent aggregation; (O) Adding the TP53S149F amyloid seed solution to WT TP53 in a 1:100 ratio induced fibril growth. P Protein aggregates created by mutant TP53 form spontaneously and can be seen by the naked eye (arrow).
