Fig. 5.

Synchrotron SAXS profiles of solutions of taxol-stabilized microtubules (MTs) as a function of increasing divalent ion concentration for ZnCl₂ (2+), CoCl₂ (2+), MnCl₂ (2+), and MgCl₂ (2+). The data show a similar trend where below a certain concentration the SAXS profiles result from the form factor of microtubules indicative of stable MTs. At higher concentrations the profiles show enhanced SAXS with no hint of the form factor peaks indicative of depolymerization of taxol-stabilized MTs as discussed in the text. (Raw data before background subtraction.)