What is the typical outer diameter of microtubules (tubulin heterodimers)?
['microtubules are highly anisotropic structures built from tubulin heterodimers. They are hollow cylindrical shells with a ∼ 25\xa0nm outer diameter', 'single microtubules (diameter 25 nm', 'The individual microtubules measured about 24 nm in outer diameter', 'Microtubules are hollow tubes some 25 nm in diameter participating in the eukaryotic cytoskeleton.', 'Microtubule assembly is accompanied by hydrolysis of GTP associated with beta-tubulin so that microtubules consist principally of "GDP-tubulin" stabilized by a short "GTP cap." Microtubules are polar, cylindrical structures some 25 nm in diameter.', 'They are hollow cylindrical shells with a ∼ 25\xa0nm outer diameter and are tens of microns long', 'Microtubule assembly is accompanied by hydrolysis of GTP associated with beta-tubulin so that microtubules consist principally of "GDP-tubulin" stabilized by a short "GTP cap." Microtubules are polar, cylindrical structures some 25 nm in diameter', 'Microtubules are hollow tubes some 25 nm in diameter participating in the eukaryotic cytoskeleton']
['Microtubules are highly anisotropic structures built from tubulin heterodimers. They are hollow cylindrical shells with a ∼ 25 nm (24nm - 25nm) outer diameter.']
['24nm - 25 nm']