Resumo: |
Kinesin-1 (conventional kinesin) is a homodimeric motor protein important for axonal transport. It has been well studied through ensemble and single-molecule assays. However, the enzymatic stepping cycle is complex, with many rate constants that are modulated by interaction of the two motor domains. This makes it difficult to predict how changes in a given rate constant may affect observable properties such as processivity, velocity, or stall force. We have written a simulation of kinesin walking using a Stochastic Simulation Algorithm. The model allows for interactions between the heads, and includes states that are not considered part of the normal cycle. This adds to the complexity of the model but also allows for probing rare events, such as those that lead to a finite processivity. Also included are rate constant dependencies on force and concentrations of ATP, ADP, and Pi, which may provide insight into other processes under investigation, such as kinesin backstepping. We intend to use the simulation to aid in interpreting our own gliding motility assay results and to place upper and lower limits on values for rate constants. Our source and executable codes will be freely available.

Acknowledgements: This work was supported by the DTRA CB Basic Research Program under Grant No. HDTRA1-09-1-008.
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