Rhodamine phalloidin F-actin: critical concentration versus tensile strength.
The mechanic and elastic properties of rhodamine phalloidin F-actin were investigated as a function of the ionic strength and in the absence of Mg2+. By increasing ionic strength from 3 to 19 mM, critical concentration decreased from 146 to 36 nM and the yield strength increased from 5.6 pN to 28.6 pN. At the ionic strength of 12-13 mM, the elastic modulus by stretching increased by 330-430 kP. nm-1 up to the break point, where it was 38-44.2 MP. The work required to break the filament, 403-439 kJ.M-1 provides an estimate of the free energy of annealing of rhodamine phalloidin F-actin, the annealing constant being 2.8 x 1074 M-1.
Adami
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Dipartimento di Biochimica e Biologia Molecalare, Universitá di Ferrara, Italy.
Choquet
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Grazi
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D000199:Actins / Q000737:chemistry*; D000818:Animals; D001696:Biomechanical Phenomena; D004548:Elasticity; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D009994:Osmolar Concentration; D010590:Phalloidine; D011817:Rabbits; D012235:Rhodamines; D013718:Tensile Strength; D013816:Thermodynamics
D000199:Actins; D005456:Fluorescent Dyes; D012235:Rhodamines; D010590:Phalloidine