scholarly journals Reversal of the cross-bridge force-generating transition by photogeneration of phosphate in rabbit psoas muscle fibres.

1992 ◽  
Vol 451 (1) ◽  
pp. 247-278 ◽  
Author(s):  
J A Dantzig ◽  
Y E Goldman ◽  
N C Millar ◽  
J Lacktis ◽  
E Homsher
Keyword(s):  
Psoas Muscle ◽  
Muscle Fibres ◽  
Rabbit Psoas ◽  
Cross Bridge ◽  
The Cross

BDM affects nucleotide binding and force generation steps of the cross-bridge cycle in rabbit psoas muscle fibers

1994 ◽  
Vol 266 (2) ◽  
pp. C437-C447 ◽  
Author(s):  
Y. Zhao ◽  
M. Kawai
Keyword(s):  
Equilibrium Constants ◽  
Muscle Fibers ◽  
Psoas Muscle ◽  
Isometric Tension ◽  
Activation Mechanism ◽  
Phosphate Binding ◽  
Rabbit Psoas ◽  
Cross Bridge ◽  
The Cross ◽  
Cross Bridges

The effect of 2,3-butanedione monoxime (BDM) on elementary steps of the cross-bridge cycle was studied with the sinusoidal analysis technique in skinned rabbit psoas muscle fibers. Our results showed that isometric tension and stiffness decreased progressively with an increase in the BDM concentration. The MgATP and MgADP binding constants increased 27 and 6 times, respectively, when BDM was increased from 0 to 18 mM, whereas the phosphate binding constant did not change significantly. The equilibrium constants of the ATP isomerization and detachment step were not sensitive to BDM, whereas the equilibrium constant of the attachment (power stroke) step decreased with BDM. Thus, in the presence of BDM, the number of attached cross bridges decreases; more cross bridges accumulate in the detached state, causing isometric tension and stiffness to decline. However, our detailed analysis shows that the decrease in the number of attached cross bridges is approximately 40%, which is not adequate to account for the 84% decrease in the isometric tension when 18 mM BDM was present. Therefore we suggest that a thin-filament activation mechanism is also affected by BDM.

scholarly journals Cross-bridge kinetics in the presence of MgADP investigated by photolysis of caged ATP in rabbit psoas muscle fibres.

1991 ◽  
Vol 432 (1) ◽  
pp. 639-680 ◽  
Author(s):  
J A Dantzig ◽  
M G Hibberd ◽  
D R Trentham ◽  
Y E Goldman
Keyword(s):  
Psoas Muscle ◽  
Muscle Fibres ◽  
Rabbit Psoas ◽  
Caged Atp ◽  
Cross Bridge

scholarly journals Adenosine diphosphate and strain sensitivity in myosin motors

2004 ◽  
Vol 359 (1452) ◽  
pp. 1867-1877 ◽  
Author(s):  
K. C. Holmes ◽  
D. R. Trentham ◽  
R. Simmons ◽  
Miklós Nyitrai ◽  
Michael A. Geeves
Keyword(s):  
Adenosine Diphosphate ◽  
Release Mechanism ◽  
Muscle Fibres ◽  
Strain Sensing ◽  
Shortening Velocity ◽  
Sensing Mechanism ◽  
Cross Bridge ◽  
Published Evidence ◽  
Adp Release ◽  
The Cross

The release of adenosine diphosphate (ADP) from the actomyosin cross–bridge plays an important role in the adenosine–triphosphate–driven cross–bridge cycle. In fast contracting muscle fibres, the rate at which ADP is released from the cross–bridge correlates with the maximum shortening velocity of the muscle fibre, and in some models the rate of ADP release defines the maximum shortening velocity. In addition, it has long been thought that the rate of ADP release could be sensitive to the load on the cross–bridge and thereby provide a molecular explanation of the Fenn effect. However, direct evidence of a strain–sensitive ADP–release mechanism has been hard to come by for fast muscle myosins. The recently published evidence for a strain–sensing mechanism involving ADP release for slower muscle myosins, and in particular non–muscle myosins, is more compelling and can provide the mechanism of processivity for motors such as myosin V. It is therefore timely to examine the evidence for this strain–sensing mechanism. The evidence presented here will argue that a strain–sensitive mechanism of ADP release is universal for all myosins but the basic mechanism has evolved in different ways for different types of myosin. Furthermore, this strain–sensing mechanism provides a way of coordinating the action of multiple myosin motor domains in a single myosin molecule, or in complex assemblies of myosins over long distances without invoking a classic direct allosteric or cooperative communication between motors.

scholarly journals The Length of Cooperative Units on the Thin Filament in Rabbit Psoas Muscle Fibres

2002 ◽  
Vol 87 (6) ◽  
pp. 691-697 ◽  
Author(s):  
Wei Ding ◽  
Hideaki Fujita ◽  
Masataka Kawai
Keyword(s):  
Thin Filament ◽  
Psoas Muscle ◽  
Muscle Fibres ◽  
Rabbit Psoas ◽  
Cooperative Units
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