Implications of diffusion-controlled limit for processivity of dimeric kinesin head domains.
Implications of diffusion-controlled limit for processivity of dimeric kinesin head domains.
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作者：
D. Hackney
根据微管近似为100%效率的高伸长椭球吸附器，DKH392激动素头域的二聚体ADP复合体与微管结合的扩散限制速率估计为2-3×10(7)M-1 S-1。这一理论双分子速率大约比DKH392的实验速率kcat/KMT0.5小100倍，该实验速率是通过微管刺激稳态ATPase速率而确定的。这两个双分子速率估计值之间的巨大差异表明，二聚体DKH392很可能在每次与微管的扩散相遇时水解多个ATP分子。
The diffusion-limited rate for association of the ADP complex of dimeric DKH392 kinesin head domains with a microtubule was estimated to be 2-3 x 10(7) M-1 s-1 based on approximation of a microtubule as a highly elongated prolate ellipsoidal adsorber of 100% efficiency. This theoretical bimolecular rate is approximately 100-fold smaller than the experimental rate, kcat/KMT0.5, for DKH392 that was determined from the stimulation of the steady-state ATPase rate by microtubules. The large difference between these two estimates of the bimolecular rate indicates that it is likely that dimeric DKH392 hydrolyzes multiple ATP molecules during each diffusional encounter with a microtubule.