Effect of Nucleotides on Thermal Transitions of Myosin |
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| Authors: | Lőrinczy D Gaszner B Könczöl F Belágyi J |
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| Institution: | (1) Institute of Biophysics, University Medical School of Pécs, Hungary;(2) Central Research Laboratory, University Medical School of Pécs, Hungary;(3) Institute of Forensic Medicine, University Medical School of Pécs, P.O. Box 99, H-7601 Pécs, Hungary |
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| Abstract: | The internal dynamics and the thermal stability of myosin in rabbit psoas muscle fibres in different intermediate states of
the ATP hydrolysis cycle were studied by differential scanning calorimetry (DSC) and electron paramagnetic resonance (EPR)
spectroscopy. Three overlapping endotherms were detected in rigor, in strongly binding and weakly binding state of myosin
to actin. The transition at 58.4°C can be assigned to the nucleotide-binding domain. The transition at highest temperature
represents the unfolding of the actin and the contributions arising from the actin-myosin interaction. The transition of 54°C
reflects the interaction between the subunits of myosin. Nucleotide binding induced shifts of the melting temperatures and
produced variations in the calorimetric enthalpy changes. The changes of the EPR parameters indicated local rearrangements
of the internal structure in myosin heads.
This revised version was published online in August 2006 with corrections to the Cover Date. |
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| Keywords: | conformation of myosin DSC EPR spin labelling |
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