The Study Of Kinesin Kinetic Properties

As a kind of motor protein,the main function of Kinesin is to move directionally in cells with the energy given by hydrolysis ATP,completing tasks such as transporting cargoes and building microtubes.Kinesin is indispensable in various cells and is necessary for life activities.Since it is discovered,researchers have been working hard to explore the mysteries of kinesin.Experimental work has made great progress,successively obtaining its kinetic characteristics such as step size,speed and moving length.In theory studies,some models have been established and successfully explaining some experimental phenomena.However,these models cannot be compared with experiments.The main problem is that when considering a detailed process in the model,it will be difficult to calculate and impossible to give an analytical solution.If the model is oversimplified,it will be way different from the actual situation and lose some rationality.To solve these problems,certain attempts have been made.Kinesin walks by a "hand-over-hand" mechanism.In this mode of motion,two heads are considering the same so that they can be studied separately,so we study single-headed chemical circulation process.When ATP is converted to ADP,the release rate of Pi is rapidly.The role of Pi in the chemical cycle is not required in the cycle,only the interaction between ADP and ATP and kinesin is considered.Based on these assumptions,we simplified the traditional complex models and established a four-state mechanochemical model.We calculated the change of dwell time,velocity and run length under different ATP,ADP and load conditions.Compared with traditional models,this model not only has a simple structure to calculate,but also in line with the actual situation which contains the main factors of walking.The results can be compared with experiment.By calculation,the analytical solution of the dwell time and velocity is given,and the distribution rate of dwell time and velocity are obtained.When calculating the influence of load on kinesin,the effect of the neck linker on free energy is taken into account based on the properties of kinesin.When calculating the run length,it is considered that the slide probability is mainly affected by the proportion of separated state.The theoretical results correspond to the experiments.We provide a new direction for the study of kinesin.