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Shigeru Chaen - One of the best experts on this subject based on the ideXlab platform.
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basic properties of atp induced myosin Head Movement in hydrated myosin filaments studied using the gas environmental chamber
Micron, 2018Co-Authors: Haruo Sugi, Tsuyoshi Akimoto, Shigeru ChaenAbstract:Although more than 50 years have passed since the monumental discovery of Huxley and Hanson that muscle contraction results from relative sliding between actin and myosin filaments, coupled with ATP hydrolysis, the mechanism underlying the filament sliding still remains to be a mystery. It is generally believed that the myofilament sliding is caused by cyclic attachment-detachment between myosin Heads in myosin filaments and myosin-binding sites in actin filaments. Attempts to prove the myosin Head Movement using techniques of X-ray diffraction and chemical probes attached to myosin Heads have failed to obtain clear results because of the asynchronous nature of myosin Head Movement. Using the gas environmental chamber (EC) attached to an electron microscope, we succeeded in recording myosin Head Movement in hydrated myosin filaments, coupled with ATP hydrolysis with the following results: (1)In the absence of actin filaments, myosin Heads fluctuate around a definite neutral position, so that their time-averaged position remains unchanged; (2) On ATP application, myosin Heads bind with ATP to be in the charged-up state, M-ADP-Pi, and perform a recovery stroke in the direction away from the myosin filament central bare zone and stay in the post-recovery stroke position; (3) In the actin-myosin filament mixture, myosin Heads form rigor linkages with actin, and bind with applied ATP to be in the charged-up state, M-ADP-Pi, and perform a power stroke in the direction towards the myosin filament bare zone, while releasing ADP and Pi to stay in the post-power stroke position; (4) In both recovery and power strokes, myosin Heads in the non charged-up state return to the neutral position. These results indicate that the charged-up myosin Heads decide their direction of Movement without being guided by actin filaments.
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dynamic electron microscopy of atp induced myosin Head Movement in living muscle thick filaments
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Haruo Sugi, Tsuyoshi Akimoto, Shigeru Chaen, Kazuo Sutoh, Noboru Oishi, Suechika SuzukiAbstract:Although muscle contraction is known to result from Movement of the myosin Heads on the thick filaments while attached to the thin filaments, the myosin Head Movement coupled with ATP hydrolysis still remains to be investigated. Using a gas environmental (hydration) chamber, in which biological specimens can be kept in wet state, we succeeded in recording images of living muscle thick filaments with gold position markers attached to the myosin Heads. The position of individual myosin Heads did not change appreciably with time in the absence of ATP, indicating stability of the myosin Head mean position. On application of ATP, the position of individual myosin Heads was found to move by ≈20 nm along the filament axis, whereas no appreciable Movement of the filaments was detected. The ATP-induced myosin Head Movement was not observed in filaments in which ATPase activity of the myosin Heads was eliminated. Application of ADP produced no appreciable myosin Head Movement. These results show that the ATP-induced myosin Head Movement takes place in the absence of the thin filaments. Because ATP reacts rapidly with the myosin Head (M) to form the complex (M⋅ADP⋅Pi) with an average lifetime of >10 s, the observed myosin Head Movement may be mostly associated with reaction, M + ATP → M⋅ADP⋅Pi. This work will open a new research field to study dynamic structural changes of individual biomolecules, which are kept in a living state in an electron microscope.
Haruo Sugi - One of the best experts on this subject based on the ideXlab platform.
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basic properties of atp induced myosin Head Movement in hydrated myosin filaments studied using the gas environmental chamber
Micron, 2018Co-Authors: Haruo Sugi, Tsuyoshi Akimoto, Shigeru ChaenAbstract:Although more than 50 years have passed since the monumental discovery of Huxley and Hanson that muscle contraction results from relative sliding between actin and myosin filaments, coupled with ATP hydrolysis, the mechanism underlying the filament sliding still remains to be a mystery. It is generally believed that the myofilament sliding is caused by cyclic attachment-detachment between myosin Heads in myosin filaments and myosin-binding sites in actin filaments. Attempts to prove the myosin Head Movement using techniques of X-ray diffraction and chemical probes attached to myosin Heads have failed to obtain clear results because of the asynchronous nature of myosin Head Movement. Using the gas environmental chamber (EC) attached to an electron microscope, we succeeded in recording myosin Head Movement in hydrated myosin filaments, coupled with ATP hydrolysis with the following results: (1)In the absence of actin filaments, myosin Heads fluctuate around a definite neutral position, so that their time-averaged position remains unchanged; (2) On ATP application, myosin Heads bind with ATP to be in the charged-up state, M-ADP-Pi, and perform a recovery stroke in the direction away from the myosin filament central bare zone and stay in the post-recovery stroke position; (3) In the actin-myosin filament mixture, myosin Heads form rigor linkages with actin, and bind with applied ATP to be in the charged-up state, M-ADP-Pi, and perform a power stroke in the direction towards the myosin filament bare zone, while releasing ADP and Pi to stay in the post-power stroke position; (4) In both recovery and power strokes, myosin Heads in the non charged-up state return to the neutral position. These results indicate that the charged-up myosin Heads decide their direction of Movement without being guided by actin filaments.
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dynamic electron microscopy of atp induced myosin Head Movement in living muscle thick filaments
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Haruo Sugi, Tsuyoshi Akimoto, Shigeru Chaen, Kazuo Sutoh, Noboru Oishi, Suechika SuzukiAbstract:Although muscle contraction is known to result from Movement of the myosin Heads on the thick filaments while attached to the thin filaments, the myosin Head Movement coupled with ATP hydrolysis still remains to be investigated. Using a gas environmental (hydration) chamber, in which biological specimens can be kept in wet state, we succeeded in recording images of living muscle thick filaments with gold position markers attached to the myosin Heads. The position of individual myosin Heads did not change appreciably with time in the absence of ATP, indicating stability of the myosin Head mean position. On application of ATP, the position of individual myosin Heads was found to move by ≈20 nm along the filament axis, whereas no appreciable Movement of the filaments was detected. The ATP-induced myosin Head Movement was not observed in filaments in which ATPase activity of the myosin Heads was eliminated. Application of ADP produced no appreciable myosin Head Movement. These results show that the ATP-induced myosin Head Movement takes place in the absence of the thin filaments. Because ATP reacts rapidly with the myosin Head (M) to form the complex (M⋅ADP⋅Pi) with an average lifetime of >10 s, the observed myosin Head Movement may be mostly associated with reaction, M + ATP → M⋅ADP⋅Pi. This work will open a new research field to study dynamic structural changes of individual biomolecules, which are kept in a living state in an electron microscope.
Bryan K Smith - One of the best experts on this subject based on the ideXlab platform.
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signal decomposition method of evaluating Head Movement to measure induced forelimb lameness in horses trotting on a treadmill
Equine Veterinary Journal, 2010Co-Authors: Kevin G Keegan, David A Wilson, Bryan K SmithAbstract:Summary In horses at a trot, the Head moves up and down twice in one stride. In horses with unilateral forelimb lameness this Movement is asymmetric. Computer-assisted kinematic analysis of vertical Head Movement can be used to quantify objectively lameness in horses in clinical trials. However, in mild lameness, absolute measurements of vertical Head height may not be sensitive enough to detect small differences in lameness, and extraneous Head Movement by the horse due to curiosity, excitement or nervousness interferes with the accurate measurement of vertical Head Movement asymmetry. We describe a simple, signal-decompensation method of evaluating vertical Head Movement using a model of induced mild foot lameness in 9 horses. The technique assumes that the vertical Head Movement pattern can be broken down into 3 components; the vertical Head Movement caused by forelimb lameness (A1), the amplitude of the natural biphasic vertical Head Movement (A2) and extraneous Head Movement. Extraneous Head Movement is mathematically removed from the vertical Head Movement pat tern. A1 and A2 are then calculated. After induction of lameness, mean A1 increased by 1.63 cm (range 0.10–3.33 cm, P = 0.005). Mean A2 did not significantly change after lameness induction. Error in reproduction of the original Head Movement pattern was 0.3–0.5%. We calculated that a hypothetical clinical trial would require 12 subjects for testing to be 80% certain that this difference would be successfully detected using this method of lameness evaluation.
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signal decomposition method of evaluating Head Movement to measure induced forelimb lameness in horses trotting on a treadmill
Equine Veterinary Journal, 2010Co-Authors: Kevin G Keegan, David A Wilson, P F Pai, Bryan K SmithAbstract:Summary In horses at a trot, the Head moves up and down twice in one stride. In horses with unilateral forelimb lameness this Movement is asymmetric. Computer-assisted kinematic analysis of vertical Head Movement can be used to quantify objectively lameness in horses in clinical trials. However, in mild lameness, absolute measurements of vertical Head height may not be sensitive enough to detect small differences in lameness, and extraneous Head Movement by the horse due to curiosity, excitement or nervousness interferes with the accurate measurement of vertical Head Movement asymmetry. We describe a simple, signal-decompensation method of evaluating vertical Head Movement using a model of induced mild foot lameness in 9 horses. The technique assumes that the vertical Head Movement pattern can be broken down into 3 components; the vertical Head Movement caused by forelimb lameness (A1), the amplitude of the natural biphasic vertical Head Movement (A2) and extraneous Head Movement. Extraneous Head Movement is mathematically removed from the vertical Head Movement pat tern. A1 and A2 are then calculated. After induction of lameness, mean A1 increased by 1.63 cm (range 0.10–3.33 cm, P = 0.005). Mean A2 did not significantly change after lameness induction. Error in reproduction of the original Head Movement pattern was 0.3–0.5%. We calculated that a hypothetical clinical trial would require 12 subjects for testing to be 80% certain that this difference would be successfully detected using this method of lameness evaluation.
Suechika Suzuki - One of the best experts on this subject based on the ideXlab platform.
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dynamic electron microscopy of atp induced myosin Head Movement in living muscle thick filaments
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Haruo Sugi, Tsuyoshi Akimoto, Shigeru Chaen, Kazuo Sutoh, Noboru Oishi, Suechika SuzukiAbstract:Although muscle contraction is known to result from Movement of the myosin Heads on the thick filaments while attached to the thin filaments, the myosin Head Movement coupled with ATP hydrolysis still remains to be investigated. Using a gas environmental (hydration) chamber, in which biological specimens can be kept in wet state, we succeeded in recording images of living muscle thick filaments with gold position markers attached to the myosin Heads. The position of individual myosin Heads did not change appreciably with time in the absence of ATP, indicating stability of the myosin Head mean position. On application of ATP, the position of individual myosin Heads was found to move by ≈20 nm along the filament axis, whereas no appreciable Movement of the filaments was detected. The ATP-induced myosin Head Movement was not observed in filaments in which ATPase activity of the myosin Heads was eliminated. Application of ADP produced no appreciable myosin Head Movement. These results show that the ATP-induced myosin Head Movement takes place in the absence of the thin filaments. Because ATP reacts rapidly with the myosin Head (M) to form the complex (M⋅ADP⋅Pi) with an average lifetime of >10 s, the observed myosin Head Movement may be mostly associated with reaction, M + ATP → M⋅ADP⋅Pi. This work will open a new research field to study dynamic structural changes of individual biomolecules, which are kept in a living state in an electron microscope.
Tsuyoshi Akimoto - One of the best experts on this subject based on the ideXlab platform.
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basic properties of atp induced myosin Head Movement in hydrated myosin filaments studied using the gas environmental chamber
Micron, 2018Co-Authors: Haruo Sugi, Tsuyoshi Akimoto, Shigeru ChaenAbstract:Although more than 50 years have passed since the monumental discovery of Huxley and Hanson that muscle contraction results from relative sliding between actin and myosin filaments, coupled with ATP hydrolysis, the mechanism underlying the filament sliding still remains to be a mystery. It is generally believed that the myofilament sliding is caused by cyclic attachment-detachment between myosin Heads in myosin filaments and myosin-binding sites in actin filaments. Attempts to prove the myosin Head Movement using techniques of X-ray diffraction and chemical probes attached to myosin Heads have failed to obtain clear results because of the asynchronous nature of myosin Head Movement. Using the gas environmental chamber (EC) attached to an electron microscope, we succeeded in recording myosin Head Movement in hydrated myosin filaments, coupled with ATP hydrolysis with the following results: (1)In the absence of actin filaments, myosin Heads fluctuate around a definite neutral position, so that their time-averaged position remains unchanged; (2) On ATP application, myosin Heads bind with ATP to be in the charged-up state, M-ADP-Pi, and perform a recovery stroke in the direction away from the myosin filament central bare zone and stay in the post-recovery stroke position; (3) In the actin-myosin filament mixture, myosin Heads form rigor linkages with actin, and bind with applied ATP to be in the charged-up state, M-ADP-Pi, and perform a power stroke in the direction towards the myosin filament bare zone, while releasing ADP and Pi to stay in the post-power stroke position; (4) In both recovery and power strokes, myosin Heads in the non charged-up state return to the neutral position. These results indicate that the charged-up myosin Heads decide their direction of Movement without being guided by actin filaments.
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dynamic electron microscopy of atp induced myosin Head Movement in living muscle thick filaments
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Haruo Sugi, Tsuyoshi Akimoto, Shigeru Chaen, Kazuo Sutoh, Noboru Oishi, Suechika SuzukiAbstract:Although muscle contraction is known to result from Movement of the myosin Heads on the thick filaments while attached to the thin filaments, the myosin Head Movement coupled with ATP hydrolysis still remains to be investigated. Using a gas environmental (hydration) chamber, in which biological specimens can be kept in wet state, we succeeded in recording images of living muscle thick filaments with gold position markers attached to the myosin Heads. The position of individual myosin Heads did not change appreciably with time in the absence of ATP, indicating stability of the myosin Head mean position. On application of ATP, the position of individual myosin Heads was found to move by ≈20 nm along the filament axis, whereas no appreciable Movement of the filaments was detected. The ATP-induced myosin Head Movement was not observed in filaments in which ATPase activity of the myosin Heads was eliminated. Application of ADP produced no appreciable myosin Head Movement. These results show that the ATP-induced myosin Head Movement takes place in the absence of the thin filaments. Because ATP reacts rapidly with the myosin Head (M) to form the complex (M⋅ADP⋅Pi) with an average lifetime of >10 s, the observed myosin Head Movement may be mostly associated with reaction, M + ATP → M⋅ADP⋅Pi. This work will open a new research field to study dynamic structural changes of individual biomolecules, which are kept in a living state in an electron microscope.
