[Tropomyosin from smooth and skeletal muscles initiates various conformational changes in skeletal F-actin].
Changes in F-actin conformation in myosin-free single ghost fibers of rabbit skeletal muscle induced by the binding of skeletal and gizzard tropomyosin to F-actin were studied by measuring intrinsic tryptophan-polarized fluorescence of F-actin. It was found that skeletal and gizzard tropomyosin binding to F-actin initiate different conformational changes in actin filaments. Skeletal tropomyosin inhibits, while gizzard tropomyosin activates the Mg2+-ATPase activity of skeletal actomyosin. It is supposed that in muscle fibers tropomyosin modulates the ATPase activity of actomyosin via conformational changes in F-actin.
Borovikov
Iu S
IuS
Dobrovol'skiĭ
Z
Z
Aksenova
N B
NB
Dabrovska
R
R
D000199:Actins / Q000378:metabolism*; D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism; D004789:Enzyme Activation; D005453:Fluorescence; D009130:Muscle, Smooth / Q000032:analysis*; D009132:Muscles / Q000032:analysis*; D011487:Protein Conformation; D011817:Rabbits; D014335:Tropomyosin / Q000502:physiology*
D000199:Actins; D014335:Tropomyosin; D000205:Actomyosin; D017301:Ca(2+) Mg(2+)-ATPase
Tropomiozin iz gladkikhh i skeletnykh myshts initsiiruet razlichnye po kharakteru konformatsionnye izmeneniia skeletnogo F-aktina.