Engineering The Neck Hinge Reshapes The Processive Movement of Kinesin-3

改造颈部铰链区重塑驱动蛋白3的持续运动能力

Objective In kinesin-3,the neck coil correlates with the following segments to form an extended neck that contains a characteristic hinge diverse from a proline in KIF13B to a long flexible linker in KIF1A.The function of this neck hinge for controlling processive movement,however,remains unclear.Methods We made a series of modifications to the neck hinges of KIF13B and KIF1A and tested their movement using a single-molecule motility assay.Results In KIF13B,the insertion of flexible residues before or after the proline differentially impacts the processivity or velocity,while the removal of this proline increases the both.In KIF1A,the deletion of entire flexible neck hinge merely enhances the processivity.The engineering of these hinge-truncated necks of kinesin-3 into kinesin-1 similarly boosts the processive movement of kinesin-1.Conclusion The neck hinge in kinesin-3 controls its processive movement and proper modifications tune the motor motility,which provides a novel strategy to reshape the processive movement of kinesin motors.

目的驱动蛋白3的颈部螺旋与其后的蛋白质序列相互关联,形成一个延长的颈部,其中包含一个特征铰链结构。该特征性铰链在不同的驱动蛋白中表现出多样性,在驱动蛋白KIF13B中,这个铰链仅由一个脯氨酸残基组成,而在驱动蛋白KIF1A中,则由一个长的柔性无规卷曲构成。然而,这个颈部铰链在控制驱动蛋白持续运动方面的功能仍不明确。方法本文对KIF13B和KIF1A的颈部铰链区的氨基酸残基进行突变改造,并通过单分子运动实验研究铰链区突变对驱动蛋白运动行为的影响。结果在KIF13B中,在铰链区--脯氨酸前后插入柔性残基对其运动的速度以及持续性都有不同程度的影响,而去除该脯氨酸则可以同时提高运动速度和持续性。在KIF1A中,删除整个柔性颈部铰链仅仅增强了其运动的持续性。同时,把驱动蛋白1的颈部铰链区用改造后的驱动蛋白3的颈部铰链区进行替换,同样能够提高驱动蛋白1的持续运动能力。结论驱动蛋白3颈部铰链控制其持续运动能力,适当改造可以调整马达的运动行为,这为重塑驱动蛋白马达的持续运动提供了一种新策略。