The molecular structure of a higher plant myosin with two 174 kD heavy chains purified from the tendrils of Luffa cylindrica(L.) Roem. was viewed by electron microscopy. The myosin exhibited actin-activated MgATPase activity and could be recognized immunologically by a monoclonal antibody against the skeletal muscle myosin. Electron micrographs of rotary shadowed images of this protein revealed that it had two heads with size and shape similar to those of the skeletal muscle myosin and a relatively short tail in comparison with the conventional myosin. Luffa tendril actin filaments were also visualized and occasionally other Luffa myosin-like proteins with globular structure at the tail ends were also observed. The structural similarity and immunological cross reactivity with antibodies against muscle myosin demonstrate that the 174 kD Luffa tendril myosin is a double-headed myosin. The possible involvement of myosin-actin interactions in Luffa tendril contact coiling will be the subject of further research.
丝瓜肌球蛋白的电子显微学研究
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