Persistence length of titin from rabbit skeletal muscles measured with scattering and microrheology techniques.
The persistence length of titin from rabbit skeletal muscles was measured using a combination of static and dynamic light scattering, and neutron small angle scattering. Values of persistence length in the range 9-16 nm were found for titin-II, which corresponds to mainly physiologically inelastic A-band part of the protein, and for a proteolytic fragment with 100-nm contour length from the physiologically elastic I-band part. The ratio of the hydrodynamic radius to the static radius of gyration indicates that the proteins obey Gaussian statistics typical of a flexible polymer in a -solvent. Furthermore, measurements of the flexibility as a function of temperature demonstrate that titin-II and the I-band titin fragment experience a similar denaturation process; unfolding begins at 318 K and proceeds in two stages: an initial gradual 50% change in persistence length is followed by a sharp unwinding transition at 338 K. Complementary microrheology (video particle tracking) measurements indicate that the viscoelasticity in dilute solution behaves according to the Flory/Fox model, providing a value of the radius of gyration for titin-II (63 +/- 1 nm) in agreement with static light scattering and small angle neutron scattering results.
Di Cola
Emanuela
E
Polymers and Complex Fluids, Department of Physics and Astronomy, University of Leeds, UK.
Waigh
Thomas A
TA
Trinick
John
J
Tskhovrebova
Larissa
L
Houmeida
Ahmed
A
Pyckhout-Hintzen
Wim
W
Dewhurst
Charles
C
D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D064211:Connectin; D004548:Elasticity; D066298:In Vitro Techniques; D008027:Light; D009124:Muscle Proteins / Q000737:chemistry*; D018482:Muscle, Skeletal / Q000737:chemistry*; D009502:Neutrons; D011487:Protein Conformation; D011494:Protein Kinases / Q000737:chemistry*; D011817:Rabbits; D012212:Rheology; D012542:Scattering, Radiation; D013696:Temperature
D064211:Connectin; D009124:Muscle Proteins; D011494:Protein Kinases