A solution of pure -tubulin dimers is thought to nucleate microtubules by forming a linear protofilament about

Question:

A solution of pure αβ-tubulin dimers is thought to nucleate microtubules by forming a linear protofilament about seven dimers in length. At that point, the probabilities that the next αβ-dimer will bind laterally or to the end of the protofilament are about equal. The critical event for microtubule formation is thought to be the first lateral association (Figure Q16–2). How does lateral association promote the subsequent rapid formation of a microtubule?

Figure Q16-2

LINEAR GROWTH LATERAL ASSOCIATION