Contractility of Myofibrils with Reconstituted Z-Disks

概要

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Reconstitution of Z-disks extracted with a low ionic strength solution by incubating proteins released from myofibrils by Ca2+ -activated factor (CAF) with Z-disk-extracted fiber bundles was successful, but the physiological activity of the fiber bundles with reconstituted Z-disks has not been studied. To elucidate the relationships between the structure of Z-disks and physiological activity of myofibrils, the contractilities of intact, Z-disk-extracted and -reconstituted fiber bundles were studied by optical and electron microscopy. Intact fiber bundles that contracted immediately after the addition of contracting solution (Mg2+ -ATP solution) showed the disappearance of the I-band and the formation of a double overlap of thin filaments in the center of the A-band. The contractility of the fiber bundles decreased with the progress of extraction of Z-disks, and formation of the double overlap of thin filaments in the center of the A-band was not observed. The fiber bundles with Z-disks reconstituted recovered the mechanism of contraction similar to that of the intact fiber bundles. When the Z-disks were removed by CAF instead of the low ionic strength solution, the reconstitution of Z-disks was not successful and therefore the contractility of the fiber bundles was not recovered.
社団法人日本農芸化学会の論文