Muscle myosin performance measured with a synthetic nanomachine reveals a class‐specific Ca 2+ ‐sensitivity of the frog myosin II isoform
| العنوان: | Muscle myosin performance measured with a synthetic nanomachine reveals a class‐specific Ca 2+ ‐sensitivity of the frog myosin II isoform |
|---|---|
| المؤلفون: | Dan Cojoc, Irene Pertici, Pasquale Bianco, Vincenzo Lombardi, Lorenzo Bongini, Giulio Bianchi, Dietmar J. Manstein, Manuel H. Taft |
| المصدر: | The Journal of Physiology. 599:1815-1831 |
| بيانات النشر: | Wiley, 2021. |
| سنة النشر: | 2021 |
| مصطلحات موضوعية: | 0301 basic medicine, Physiology, Chemistry, Skeletal muscle, macromolecular substances, Isometric exercise, Rana, Protein filament, 03 medical and health sciences, 030104 developmental biology, 0302 clinical medicine, medicine.anatomical_structure, Myosin, Biophysics, medicine, Binding site, Gelsolin, 030217 neurology & neurosurgery, Actin |
| الوصف: | KEY POINTS A nanomachine made of an ensemble of seven heavy-meromyosin (HMM) fragments of muscle myosin interacting with an actin filament is able to mimic the half-sarcomere generating steady force and constant-velocity shortening. To preserve Ca2+ as a free parameter, the Ca2+ -insensitive gelsolin fragment TL40 is used to attach the correctly oriented actin filament to the laser-trapped bead acting as a force transducer. The new method reveals that the performance of the nanomachine powered by myosin from frog hind-limb muscles depends on [Ca2+ ], an effect mediated by a Ca2+ -binding site in the regulatory light chain of HMM. The Ca2+ -sensitivity is class-specific because the performance of the nanomachine powered by mammalian skeletal muscle myosin is Ca2+ independent. A model simulation is able to interface the nanomachine performance with that of the muscle of origin and provides a molecular explanation of the functional diversity of muscles with different orthologue isoforms of myosin. ABSTRACT An ensemble of seven heavy-meromyosin (HMM) fragments of myosin-II purified from the hindlimb muscles of the frog (Rana esculenta) is used to drive a synthetic nanomachine that pulls an actin filament in the absence of confounding effects of other sarcomeric proteins. In the present version of the nanomachine the +end of the actin filament is attached to the laser trapped bead via the Ca2+ -insensitive gelsolin fragment TL40, making [Ca2+ ] a free parameter. Frog myosin performance in 2 mm ATP is affected by Ca2+ : in 0.1 mm Ca2+ , the isometric steady force (F0 , 15.25 pN) is increased by 50% (P = 0.004) with respect to that in Ca2+ -free solution, the maximum shortening velocity (V0 , 4.6 μm s-1 ) is reduced by 27% (P = 0.46) and the maximum power (Pmax , 7.6 aW) is increased by 21% (P = 0.17). V0 reduction is not significant for the paucity of data at low force, although it is solidified by a similar decrease (33%, P |
| تدمد: | 1469-7793 0022-3751 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::d97e90c0117c89766f86842ce8299ef5 https://doi.org/10.1113/jp280976 |
| حقوق: | CLOSED |
| رقم الأكسشن: | edsair.doi...........d97e90c0117c89766f86842ce8299ef5 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 14697793 00223751 |
|---|