The Optimized Quantum Dots Mediated Thermometry Reveals the Efficiency of Myosin Extracted from Muscle Mini Bundles.

The biophysical function of myosin in vitro has been extensively investigated in different motility assays. However, the study of myosin ATPase properties at the fiber level is still limited. In this study we aimed to optimize quantum dots (QD) mediated thermometry to measure the efficiency of myosin extracted from muscle mini bundles. A reduction in fluorescent intensity of QD reflects an increase in temperature caused by the heat release during ATP hydrolysis, denoting the efficiency of the motor protein myosin. The procedure for extracting myosin was modified from the single fiber in vitro motility assay, and the concentration of myosin was represented by the extracted total protein since the ratio of extracted myosin to total protein was constant. Moreover, the efficiency of myosin extracted from preparations containing different isoform compositions revealed that slow myosin has a lower efficiency than fast myosin, i.e., a higher amount of heat was released resulting in faster decay of QD fluorescence intensity. Thus, the optimized QD mediated thermometry provides a new sensitive approach to evaluate myosin function from a thermometrical perspective based on minimal muscle tissue.