Changes in the 5.9 nm actin layer-line on activation of frog skeletal muscles.
The intensity changes of the actin layer-lines during activation of sartorius and overstretched semitendinosus muscles were measured by using a two-dimensional X-ray detector. In both muscles, the intensity of the 5.9 nm layer-line increased without a detectable shift in the peak position. The intensity of the second layer-line increased in both muscles by a similar amount. In semitendinosus muscle, a large intensity decrease of the first actin layer-line was observed. Model calculations suggest that these results are difficult to explain in terms of a simple steric blocking model of regulation involving only a movement of tropomyosin on the actin helix.
Yagi
N
N
Department of Pharmacology, Tohoku University School of Medicine, Sendai, Japan.
Matsubara
I
I
D000199:Actins / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D066298:In Vitro Techniques; D007834:Lasers; D008954:Models, Biological; D009119:Muscle Contraction; D009132:Muscles / Q000502:physiology*; D009218:Myosins / Q000502:physiology; D009928:Organ Specificity; D011485:Protein Binding; D011892:Rana catesbeiana; D014336:Troponin / Q000378:metabolism; D014961:X-Ray Diffraction / Q000379:methods
D000199:Actins; D014336:Troponin; D009218:Myosins; D002118:Calcium