The mechanic and elastic properties of F-actin were extensively investigated, but, surprising, no attention was paid to the influence of critical concentration on tensile strength. Formally, the critical concentration is the main determinant of the free energy of the monomer-monomer interaction, thus of tensile strength. We have investigated this aspect, the influence of critical concentration on tensile strength, by stretching rhodamnine phalloidin actin filaments by a laser trap. We found that by increasing ionic strength from 3 to 19 mM, critical concentration decreased fron 146 to 36 nM and the yield strength increased from 5.6 to 28.6 pN. At the ionic strength of 12-13 mM, the elastic modulus increased by 330-430 kP/nm up to break point, were it was 38-44.2 MP. Our finding poses the question of how actin filament bears the forces, ie how thin filament supports muscle contraction.
Mechanic and elastic properties of F-actin / R. Adami, E. Grazi. ((Intervento presentato al 14. convegno Meeting of the European Cytoskeletal Forum tenutosi a Carcavelos/Oeiras nel 1999.
Mechanic and elastic properties of F-actin
R. AdamiPrimo
;
1999
Abstract
The mechanic and elastic properties of F-actin were extensively investigated, but, surprising, no attention was paid to the influence of critical concentration on tensile strength. Formally, the critical concentration is the main determinant of the free energy of the monomer-monomer interaction, thus of tensile strength. We have investigated this aspect, the influence of critical concentration on tensile strength, by stretching rhodamnine phalloidin actin filaments by a laser trap. We found that by increasing ionic strength from 3 to 19 mM, critical concentration decreased fron 146 to 36 nM and the yield strength increased from 5.6 to 28.6 pN. At the ionic strength of 12-13 mM, the elastic modulus increased by 330-430 kP/nm up to break point, were it was 38-44.2 MP. Our finding poses the question of how actin filament bears the forces, ie how thin filament supports muscle contraction.Pubblicazioni consigliate
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