Decorating actin filaments with troponin T-I complexes and acceleration of their sliding movement on myosin molecules.
Actin filaments, when partially decorated with troponin T-I complexes, can slide faster on myosin heads than those with no decoration. Purified troponin T-I complexes bind to actins, and inhibit the actin activated myosin adenosine 5'-triphosphatase activity completely when the molar ratio of troponin T-I complex to actin is increased to 1 to 1. Those actin filaments decorated with troponin T-I complexes up to 20 to 50% of their molar ratio exhibit enhancement of the velocity of sliding on myosins up to 20% compared to those without such decoration. As the molar ratio of decoration further increases, the sliding velocity decreases. These results are consistent with the observation that even if some of actin monomers do not participate in the ATPase activity directly, they can interact with myosin heads and take part in the sliding movement.
Honda
H
H
Department of BioEngineering, Nagaoka University of Technology, Japan.
Tamura
T
T
Hatori
K
K
Matsuno
K
K
D000199:Actins / Q000737:chemistry*; D000205:Actomyosin / Q000737:chemistry; D000251:Adenosine Triphosphatases / Q000737:chemistry; D009218:Myosins / Q000737:chemistry*; D014336:Troponin / Q000737:chemistry*; D020107:Troponin T
D000199:Actins; D014336:Troponin; D020107:Troponin T; D000205:Actomyosin; D000251:Adenosine Triphosphatases; D009218:Myosins