title: Flexural rigidity of singlet microtubules estimated from statistical analysis of their contour lengths and end-to-end distances.
abstract: Microtubules in solutions, observed under a dark-field microscope, show incessant Brownian movement such as translational, rotational and flexing motion. A large number of microtubules, spontaneously stuck to the under surface of a coverslip, were photographed and the contour lengths and end-to-end distances of their images were measured. From the statistical analysis of the contour lengths and end-to-end distances, a value for the parameter lambda representing the flexibility of singlet microtubules was estimated to be lambda = (6.8 +/- 0.8) . 10(-3) micrometers-1. From the value of lambda, the elastic modulus for bending, epsilon, and Young's modulus, Y, of singlet microtubules were computed to be epsilon = approximately 10(-16) and Y = approximately 10(9) dyne . cm-2, respectively. The microscopic elastic constant, k, of bonding between two tubulin monomers neighboring along the singlet microtubule was computed to be k = congruent to 10(2) dyne . cm-1. A singlet microtubule is an order of magnitude as strong against bending and as weak against stretching as an F-actin filament.
mesh_terms: D000818:Animals; D001921:Brain; D003599:Cytoskeleton / Q000502:physiology; D004548:Elasticity; D005407:Flagella / Q000502:physiology; D008870:Microtubules / Q000502:physiology* / Q000648:ultrastructure; D009068:Movement; D012399:Rotation; D013223:Statistics as Topic; D013552:Swine; D014404:Tubulin / Q000378:metabolism
chemical_list: D014404:Tubulin