Polyamine Sharing between Tubulin Dimers Favours Microtubule Nucleation and Elongation via Facilitated Diffusion
Figure 2
AFM images of microtubules assembled in the presence of various concentrations of spermidine in buffer M with 30 µM tubulin.
Scan area: 8×8 µm2. (A) Control. (B) 200 µM spermidine. (C) 800 µM spermidine. Microtubules formed in the presence of moderate concentrations of spermidine (<400 µm) had a normal appearance without any tendency for bundling. Higher spermidine concentrations lead to the apparition of shorter MTs and some aberrant structures (oligomers, aggregates, see also Figure 3).