Elastic structure in giant myofibrillar sarcomeres

在节肢动物的肌肉中，已知projectin，1200 kDa的弹性蛋白（260 nm长），将肌球蛋白连接到肌节中的Z线。在脊椎动物骨骼肌中，连接蛋白（肌联蛋白），3000 kDa的弹性蛋白，代替。节肢动物爪肌的巨大肌节中的弹性结构是如何的？螯虾爪肌肌节在静止状态下长达10 μ m。在本工作中，我们观察到3000 kDa的连接蛋白样蛋白将Z线连接到螯虾近肌和开肌肌的肌球蛋白上。通过凝溶胶蛋白处理除去肌动蛋白丝后与连接Z线和肌球蛋白丝边缘的非常细的丝结合的3000 kDa蛋白的抗体。在肌球蛋白丝的表面有突起。

In arthropod muscles, it has been known that projectin, 1200 kDa elastic protein (260 nm long), links the myosin filamentto the Z line in a sarcomere. In vertebrate skeletal muscle, connectin (titin), 3000 kDa elastic protein, does so instead.How is the elastic structure in the giant sarcomeres of arthropod claw muscle? The sarcomere length of crayfish claw muscle is as long as 10 mum at rest. Projectin can not cover several mum distance.In the present work it was observed that 3000 kDa connectin like protein links the Z line to the myosin filamentin crayfish closer and opener muscles. Antibodies to the 3000 kDa protein bound to the very thin filaments linking the Z line to the edge of the myosin filament after actin filaments were removed by the gelsolin treatment. Projectin was located to the surface of the myosin filament.