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212 Tissue Engineering and Nanotheranostics
Fig. 5. A sketch of an a/b tubulin dimer.
a and b tubulin proteins. The a and b tubulin have positive and
negative charges and taken as a pair (a “dimer”), they may be viewed
electrically as a simple battery — as used in a flashlight.
If the a/b dimers are modeled as a short cylinder, the diameter is
approximately 5 nm and the length 10 nm. Thus a typical microtu
bule filament contains approximately 40 a/b dimers.
The microtubule cylinder has 13 parallel filaments. These fila
ments are believed to be able to move longitudinally, independent of
one another. Figures 5–7 provide sketches of an a/b dimer, a fila
ment, and a microtubule cylinder.
